• Title/Summary/Keyword: Sample orientation

Search Result 358, Processing Time 0.027 seconds

A Study on the Born Global Venture Corporation's Characteristics and Performance ('본글로벌(born global)전략'을 추구하는 벤처기업의 특성과 성과에 관한 연구)

  • Kim, Hyung-Jun;Jung, Duk-Hwa
    • Journal of Global Scholars of Marketing Science
    • /
    • v.17 no.3
    • /
    • pp.39-59
    • /
    • 2007
  • The international involvement of a firm has been described as a gradual development process "a process in which the enterprise gradually increases its international involvement in many studies. This process evolves in the interplay between the development of knowledge about foreign markets and operations on one hand and increasing commitment of resources to foreign markets on the other." On the basis of Uppsala internationalization model, many studies strengthen strong theoretical and empirical support. According to the predictions of the classic stages theory, the internationalization process of firms have been recognized and characterized gradual evolution to foreign markets, so called stage theory: indirect & direct export, strategic alliance and foreign direct investment. However, termed "international new ventures" (McDougall, Shane, and Oviatt 1994), "born globals" (Knight 1997; Knight and Cavusgil 1996; Madsen and Servais 1997), "instant internationals" (Preece, Miles, and Baetz 1999), or "global startups" (Oviatt and McDougall 1994) have been used and come into spotlight in internationalization study of technology intensity venture companies. Recent researches focused on venture company have suggested the phenomenons of 'born global' firms as a contradiction to the stages theory. Especially the article by Oviatt and McDougall threw the spotlight on international entrepreneurs, on international new ventures, and on their importance in the globalising world economy. Since venture companies have, by definition. lack of economies of scale, lack of resources (financial and knowledge), and aversion to risk taking, they have a difficulty in expanding their market to abroad and pursue internalization gradually and step by step. However many venture companies have pursued 'Born Global Strategy', which is different from process strategy, because corporate's environment has been rapidly changing to globalization. The existing studies investigate that (1) why the ventures enter into overseas market in those early stage, even in infancy, (2) what make the different international strategy among ventures and the born global strategy is better to the infant ventures. However, as for venture's performance(growth and profitability), the existing results do not correspond each other. They also, don't include marketing strategy (differentiation, low price, market breadth and market pioneer) that is important factors in studying of BGV's performance. In this paper I aim to delineate the appearance of international new ventures and the phenomenons of venture companies' internationalization strategy. In order to verify research problems, I develop a resource-based model and marketing strategies for analyzing the effects of the born global venture firms. In this paper, I suggested 3 research problems. First, do the korean venture companies take some advantages in the aspects of corporate's performances (growth, profitability and overall market performances) when they pursue internationalization from inception? Second, do the korean BGV have firm specific assets (foreign experiences, foreign orientation, organizational absorptive capacity)? Third, What are the marketing strategies of korean BGV and is it different from others? Under these problems, I test then (1) whether the BGV that a firm started its internationalization activity almost from inception, has more intangible resources(foreign experience of corporate members, foreign orientation, technological competences and absorptive capacity) than any other venture firms(Non_BGV) and (2) also whether the BGV's marketing strategies-differentiation, low price, market diversification and preemption strategy are different from Non_BGV. Above all, the main purpose of this research is that results achieved by BGV are indeed better than those obtained by Non_BGV firms with respect to firm's growth rate and efficiency. To do this research, I surveyed venture companies located in Seoul and Deajeon in Korea during November to December, 2005. I gather the data from 200 venture companies and then selected 84 samples, which have been founded during 1999${\sim}$2000. To compare BGV's characteristics with those of Non_BGV, I also had to classify BGV by export intensity over 50% among five or six aged venture firms. Many other researches tried to classify BGV and Non_BGV, but there were various criterion as many as researchers studied on this topic. Some of them use time gap, which is time difference of establishment and it's first internationalization experience and others use export intensity, ration of export sales amount divided by total sales amount. Although using a mixed criterion of prior research in my case, I do think this kinds of criterion is subjective and arbitrary rather than objective, so I do mention my research has some critical limitation in the classification of BGV and Non_BGV. The first purpose of research is the test of difference of performance between BGV and Non_BGV. As a result of t-test, the research show that there are statistically efficient difference not only in the growth rate (sales growth rate compared to competitors and 3 years averaged sales growth rate) but also in general market performance of BGV. But in case of profitability performance, the hypothesis that is BGV is more profit (return on investment(ROI) compared to competitors and 3 years averaged ROI) than Non-BGV was not supported. From these results, this paper concludes that BGV grows rapidly and gets a high market performance (in aspect of market share and customer loyalty) but there is no profitability difference between BGV and Non_BGV. The second result is that BGV have more absorptive capacity especially, knowledge competence, and entrepreneur's international experience than Non_BGV. And this paper also found BGV search for product differentiation, exemption strategy and market diversification strategy while Non_BGV search for low price strategy. These results have never been dealt with other existing studies. This research has some limitations. First limitation is concerned about the definition of BGV, as I mentioned above. Conceptually speaking, BGV is defined as company pursue internationalization from inception, but in empirical study, it's very difficult to classify between BGV and Non_BGV. I tried to classify on the basis of time difference and export intensity, this criterions are so subjective and arbitrary that the results are not robust if the criterion were changed. Second limitation is concerned about sample used in this research. I surveyed venture companies just located in Seoul and Daejeon and also use only 84 samples which more or less provoke sample bias problem and generalization of results. I think the more following studies that focus on ventures located in other region, the better to verify the results of this paper.

  • PDF

The Relationship between Entrepreneurial Education and Entrepreneurial Intentions : Focusing on Moderating Effects of Entrepreneurial Orientation and Environmental Factors (창업교육과 창업의지의 관계: 기업가 지향성과 환경적 요인의 조절효과)

  • Lee, Jae-Seok;Lee, Sang-Myung
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.10 no.3
    • /
    • pp.61-74
    • /
    • 2015
  • This study attempts to empirically examine the influence of entrepreneurial education in university on entrepreneurial intentions of undergraduate and graduate students as potential entrepreneur and new moderating factors on the relationship between entrepreneurial education and entrepreneurial intentions. We suggested EO(innovativeness, risk-taking propensity, proactiveness and locus of control) and environmental factors(entrepreneurial family background and resource accessibility) as new moderating factors in the relationship. For this study, the following research questions are raised : First, is there a significant difference in entrepreneurial intentions of enrolled and unenrolled students in entrepreneurial education? Second, does entrepreneurial education affect entrepreneurial intentions positively? Finally, do EO and environmental factors have moderating effects in the relationship between entrepreneurial education and entrepreneurial intentions? In order to test our research model, the current study collected data from 265 undergraduate and graduate students who are majoring in natural sciences or engineering in Seoul National Univ., Hanyang Univ., and KAIST. To investigate our research questions and hypotheses, independent-sample T-test and hierarchical regression analysis were employed. The results of empirical analysis revealed that entrepreneurial education positively related to entrepreneurial intentions and that the relationship between entrepreneurial education and entrepreneurial intentions moderated by EO and environmental factors. First, the result showed the significant difference in entrepreneurial intentions between enrolled and unenrolled students in entrepreneurial education. Entrepreneurial intentions of students who enrolled entrepreneurial education was higher than others. Second, entrepreneurial education affected the entrepreneurial intentions positively. Finally, the moderating effects of innovativeness, risk-taking propensity, proactiveness and entrepreneurial family background among investigated six moderators were significant. entrepreneurial education-entrepreneurial intentions relationship was even stronger under high innovativeness and high proactiveness. But risk-taking propensity and entrepreneurial family background decreased the effect of entrepreneurial education on entrepreneurial intentions.

  • PDF

Oxide perovskite crystals type ABCO4:application and growth

  • Pajaczkowska, A.
    • Proceedings of the Korea Association of Crystal Growth Conference
    • /
    • 1996.06a
    • /
    • pp.258-292
    • /
    • 1996
  • In the last year great interest appears to YBCO thin films preparation on different substrate materials. Preparation of epitaxial film is a very difficult problem. There are many requirements to substrate materials that must be fullfilled. Main problems are lattice mismatch (misfit) and similarity of structure. From paper [1] or follows that difference in interatomic distances and angles of substrate and film is mire important problem than similarity of structure. In this work we present interatomic distances and angle relations between substrate materials belonging to ABCO4 group (where A-Sr or Ca, B-rare earth element, C-Al or Ga) of different orientations and YBCO thin films. There are many materials used as substrates for HTsC thin films. ABCO4 group of compounds is characterized by small dielectric constants (it is necessary for microwave applications of HTsC films), absence of twins and small misfit [2]. There most interesting compounds CaNdAlO4, SrLaAlO4 and SrLaGaO4 were investigated. All these compounds are of pseudo-perovskite structure with space group 14/mmm. This structure is very similar to structure of YBCO. SLG substrate has the lowest misfit (0.3%) and dielectric constant. For preparation of then films of substrates of this group of compound plane of <100> orientation are mainly used. Good quality films of <001> orientations are obtained [3]. In this case not only a-a misfit play role, but c-3b misfit is very important too. Sometimes, for preparation of thin films substrates of <001> and <110> orientations were manufactured [3]. Different misfits for different YBCO faces have been analyzed. It has been found that the mismatching factor for (100) face is very similar to that for (001) face so there is possibility of preparation of thin films on both orientations. SrLaAlO4(SLA) and SrLaGaO4(SLG) crystals of general formula ABCO4 have been grown by the Czochralski method. The quality of SLA and SLG crystals strongly depends on axial gradient of temperature and growth and rotation rates. High quality crystals were obtained at axial gradient of temperature near crystal-melt interface lower than 50℃/cm, growth rate 1-3 mm/h and the rotation rate changing from 10-20pm[4]. Strong anisotropy in morphology of SLA and SLG single crystals grown by the Czochralski method is clearly visible. On the basics of our considerations for ABCO4 type of the tetragonal crystals there can appear {001}, {101}, and {110} faces for ionic type model [5]. Morphology of these crystals depend on ionic-covalent character of bonding and crystal growth parameters. Point defects are observed in crystals and they are reflected in color changes (colorless, yellow, green). Point defects are detected in directions perpendicular to oxide planes and are connected with instability of oxygen position in lattice. To investigate facets formations crystals were doped with Cr3+, Er3+, Pr3+, Ba2+. Chromium greater size ion which is substituted for Al3+ clearly induces faceting. There appear easy {110} faces and SLA crystals crack even then the amount of Cr is below 0.3at.% SLG single crystals are not so sensitive to the content of chromium ions. It was also found that if {110} face appears at the beginning of growth process the crystal changes its color on the plane {110} but it happens only on the shoulder part. The projection of {110} face has a great amount of oxygen positions which can be easy defected. Pure and doped SLA and SLG crystals measured by EPR in the<110> direction show more intensive lines than in other directions which allows to suggest that the amount of oxygen defects on the {110} plane is higher. In order to find the origin of colors and their relation with the crystal stability, a set of SLA and SLG crystals were investigated using optical spectroscopy. The colored samples exhibit an absorption band stretching from the UV absorption edge of the crystal, from about 240 nm to about 550 m. In the case of colorless sample, the absorption spectrum consists of a relatively weak band in the UV region. The spectral position and intensities of absorption bands of SLA are typical for imperfection similar to color centers which may be created in most of oxide crystals by UV and X-radiation. It is pointed out that crystal growth process of polycomponent oxide crystals by Czochralski method depends on the preparation of melt and its stoichiometry, orientation of seed, gradient of temperature at crystal-melt interface, parameters of growth (rotation and pulling rate) and control of red-ox atmosphere during seeding and growth (rotation and pulling rate) and control of red-ox atmosphere during seeding and growth. Growth parameters have an influence on the morphology of crystal-melt interface, type and concentration of defects.

  • PDF

The Effect Of Job Insecurity To The Union Commitment, Dual Commitment and The Union-Related Orientation (고용불안이 노조몰입, 이중몰입, 노사관계행동지향성에 미치는 영향에 관한 연구)

  • Son, Heon-I;Jung, Hyun-Woo
    • Management & Information Systems Review
    • /
    • v.34 no.2
    • /
    • pp.131-149
    • /
    • 2015
  • Recently many organizations have engaged in widespread restructuring as well as more flexible usage of labor in an attempt to cut costs and to increase profit. As a result of lays offs resulting from frequent restructuring, many people no longer consider their jobs as permanent positions. many employees have an increased feeling of job insecurity. There structuring and following downsizing have created an uncertain environment within creased fear offer ther job losses. therefore the study of job insecurity is significant. especially To understand the relationship between job security and union-relation behaviors on the industrial relations. The purpose of this study suggested the strategies to company and union. The purpose of this study is to examine how the union-relation behaviors are influenced by the job security. This study built a exploratory model that there is causal relationship of job security to union commitment, dual commitment, and labor related behaviors. For the verification of this study model, the regression analysis was applied to the surveys of 236 members of union that are located in Busan, Gyeongnam, Ulsan, and Pohang. The result of this research shows that the job insecurity is strongly related to the union commitment and union related behaviors. According to the research, the effect that the job security affects union commitment and union related behaviors are positive. With the research outputs, we have discussed about the academic and pragmatic viewpoint. We proposed comprehensive model to verify how the job insecurity affects the union-related behaviors, and objectively analyzed the model. The research result was opposite to what the existing theories have said that high job insecurity derives high union-related behaviors. This result is meaningful because it is concerned with the social issues-present situation of Korean company, low-employment, unstable employment and so on. Moreover, this research may contribute to expand the aspect of academic research on job insecurity as there are few research conducted in korea. This research also suggests the realistic alternative of union-related behaviors because it is proved that job security can contribute to innovation activities. Also, this research implies that the matter of job insecurity is the basic need of organizational individual and presents that job security is not a notion but the alternative by using of the positional stability and situational control power. The limitation of this research is that it is only utilized the cross-sectional study. To remedy the cross-sectional study, vertical, and serial method of research is needed. And there is no enough sample to secure more comprehensive data as the targets of the research is limited to Busan and Gyeongnam regions. Finally, the measurement tool for job security is needed to be suitably modified to by the South Korea's economic, linguistic, and cultural situation.

  • PDF

Exploring Sport Consumption Style of Generation Z that the 4th Industrial revolution paid attention to: Applying Decision Tree Analysis based on Data Mining (4차 산업혁명이 주목한 Z세대의 스포츠 소비 스타일 탐색: 데이터마이닝 기반 의사결정 나무 분석 적용)

  • Shin, Jin-Ho;Lim, Young-Sam;Kim, Ji-Sun
    • Journal of the Korean Applied Science and Technology
    • /
    • v.37 no.5
    • /
    • pp.1208-1221
    • /
    • 2020
  • The purpose of this study was to provide basic data for predicting the sports consumption market that Generation Z will lead by applying data mining based decision tree analysis to explore Generation Z sports consumption style. Therefore, the survey was conducted by selecting males and females aged 19 or older as a sample among Generation Z, and data of 429 people were used for the final analysis. For data processing, frequency analysis, exploratory factor analysis, retest and reliability analysis, and decision tree analysis were performed using the SPSS statistics (ver. 21.0) program. The main results of this study are as follows. First, if the rational efficiency index is high and the aesthetic consumption index is low, the probability of being classified as a group of female was 96.8%. On the other hand, if the rational efficiency and perception of price index were low, the probability of being classified as a male group was 100%. Second, if the brand orientation, perception of price, and rational efficiency index were high, the probability of being classified as a capital area group was 97.3%. Contrary to the results presented above, the probability of being classified as a other area group was 82.1% when the brand orientation, commemoration rites, and status symbol index were low. Third, the status symbol and trend oriented index were high, and if the functionality index was low, the probability of being classified into daily life and fashion groups was 77.6%. On the contrary, if the status symbol index is low, the retention of membership and enjoy consumption index is high, the probability of being classified into exercise and competition groups was 81.0%.

The Studies of the Water-Vapour Transmission Rate and It's Proofness on the Various Commercial Polymer Films (상업용 고분자 필름의 투습속도 및 방습도에 관한 연구)

  • Hwan Kyu Suh;Jung Keun Lee
    • Journal of the Korean Chemical Society
    • /
    • v.23 no.5
    • /
    • pp.329-337
    • /
    • 1979
  • The water-vapour transmission ratios (WVTR) of the various commercial polymer films have been investigated at the constant pressure and relative humidity (RH). Water proofnesses, the reciprocals of WVTR for the various samples, were determined using a cup device and maintaining the sample films at a constant temperature ($40{\pm}1^{\circ}C$) and a constant R. H ($90{\pm}2%$) for 24 hours. The following order of the relative proofness was observed; oriented polypropyrene (O.PP) > high density polyethylene (HDPE, Inflation) > high density polyethylene (HDPE. T-die) > casted polypropylene (C. PP) > nonoriented polyester (N. PET) > low density polyethylene (LDPE) > oriented polyester (O. PET) > rigid polyvinyl chloride (Rigid PVC) > semirigid polyvinyl chloride (Semirigid PVC) > nonrigid polyvinyl chloride (Nonrigid PVC) > oriented nylon (O. Nylon) > nonoriented nylon (N. Nylon). And water proofness order was also observed to decrease with the temperature rising; HDPE (T-die) > C. PP > O. PET > LDPE > O. Nylon. The activation energies of LDPE, HDPE (T-die), C. PP, O. PET and O.Nylon films were 12.0, 11.1, 11.4, 11.7, 14.1 kcal/mole, respectively. The WVTR's of the films were increased with the polarity of polymer and the addition of plasticizer in PVC, decreased with the increase of the film thickness and mechanical orientation. The WVTR's of the laminated films O. PP/LDPE, N.Nylon/LDPE, C.PP/LDPE were also more dependent on the film thickness than the WVTR's of the single films.

  • PDF

Development of An Instrument to Measure Hope for the Cancer Patients (암환자 간호를 위한 희망 측정도구 개발)

  • 김달숙;이소우
    • Journal of Korean Academy of Nursing
    • /
    • v.28 no.2
    • /
    • pp.441-456
    • /
    • 1998
  • The purpose of this study was to develop a reliable and valid instrument to measure hope for cancer patients in Korea. This Hope Scale(Kim & Lee Hope Scale ; KLHS ) was developed based on not only critical universal attributes explaining both basic hope (generalized hope) and specific hope but also particular characteristics varing from culture and situation, which were revealed in a comprehensive review of the literature. Initially 60 items were generated from three sources : 36 items from the Q-sample used in the Kim's study, 1992, 21 representative items(statements) from the rest Q-population of the above study, 3 items related to the newly discovered category in the new qualitative study using 10 open ended question(death and dying) from the new qualitative study on the 20 cancer patients. At first 3 items were eliminated by the critique of the content validity experts, who were high experienced nurse, nursing professors. And then 4 items were eliminated in consideration of corrected item total correlation coefficiency, theoretical framework of this study. After that, 14 items were eliminated in comparing two or three items identified with the same meaning in each factor by this research team with factor loading and communality. This Hope Scale was finally constructed with 39 items. Psychometric evaluation was done on 492 adults(104 cancer patients, 388 adults who imagined who were cancer patients ranging from 18 to 76 years old. The results revealed high internal consistency Alpha coefficiency of .9351. Princial Component Factor Analysis with Varimax Rotation resulted in 8 factors with more than 1.0 of Eigenvalue. Referring to Eigenvalues, percent of variances(>60%), reproduced correlation matrix, and our theoretical framework, we decided the eight factors were the best1 solution to represent hope dimensions sufficiently. The eight factors were "confidence in possibility of cure", "sense of internal satisfaction", "being in communion", "meaning of life", "Korean hope perspectives", "belief in god", "self confidence", "self-worth". Among these factors, "confidence in possibility of cure", "sense of internal satisfaction", "Korean hope perspectives" were identified as different hope dimensions from those of Nowotny Hope Scale and Herth Hope Scale. There was significant negative correlation of r=-.4736 between this hope scale and Beck Hopelessness Scale (BHS), and significant positive correlation of r=.3685 between this hope scale and Life Orientation Test (LOT) which indicate convergent and discriminant validity. The range of hope scores was from 71 to 244, with a mean of 171.97(SD=28.16).

  • PDF

A Preliminary Study for Curriculum Building in Nursing (교육과정개발을 위한 학생측면의 기초연구 - 간호학과 학생의 자아개념과 교육자의 인식을 중심으로 -)

  • Jung Moon-Hee;Lim Nan-Young;Choi Sun-Ha;Do Keong-Jin
    • Journal of Korean Public Health Nursing
    • /
    • v.4 no.2
    • /
    • pp.35-57
    • /
    • 1990
  • This study was conducted to provide information useful in developing a nursing curriculum. The sample consisted of 158 nursing students in Hanyang University and 34 faculty members who has taught them in their college & the practical area. Data were collected by using a structured questionnaire, which consisted of general characteristics of the students & their self-concept, teacher's perception of student's professional roles. The results are summarized as follows; 1. General characteristics of the students When the students applied for the university, they decided what they would specialized in. Because the motive of application for their major was simply based on their high school records, they were admitted to their university without previous knowledge of their major. The reason why they wanted to tranfer to another course after the admission was the same as above. The level of satisfaction of their major was the highest in Freshman, but in other grades the higher the;, grades were, the more they satisfied with their major and they had a better prospects about their speciality. 2. Self-concept in profermance for their major Self-concept in horne aspects was more positive perception than in social aspects & self control aspects. It resulted from tile fact that all students were females and the nursing uniqueness was based on the spirit of humanity & service. The students who had graduated from the high school in rural area wanted to tranfer to another course and taken counsel their personal problems with their parents had higher self-concept in horne aspects. As their grades were higher, the self-concept in social aspects bacame higher. The students who were satisfied with their major and took counsel their personal problems with their parents had more positive self - concept in social aspects. Self-concept in self control aspects was lower than other aspects. The students who didn't take counsel their problems with their parents, were burdened with their educational expenses and their curriculum had more negative self-concept in self control aspects. Therefore the university should be concerned about student's welfare and provide detailed orientation about their curriculum. 3. Teacher's perception about learner's professional role The role model of democratic group leader, role models for learners facilitator in a students' reach for knowledge and teaching based on soundly researched theory showed more positive perception than other factors. Their mean values were over 4. 32. The professionalism of allnurshing area, reinforcement with reinforcement for learning, nursing as part of the meaningful context of the whole showed nagative perception. Their mean values were below 3. 00. Therefore the nurse as a teacher should try to promote the locus of nursing profession and participate in their research actively.

  • PDF

Catalog use study : with reference to universities in Daegu (대학도서관의 목록이용연구)

  • 최달현
    • Journal of Korean Library and Information Science Society
    • /
    • v.9
    • /
    • pp.241-266
    • /
    • 1982
  • This paper gives a summary and overview of a survey conducted at the catalogues of five universities in Daegu during November 1982. The major objective of this study was to secure information about user needs in order to improve the catalogue in Korean university libraries. Data was collected by a combined method of questionnaire and interview. A total of 379 respondents were taken on a randomly selected sample of catalogue users. Results of the survey can be summarized as follows: 1. Eighty-eight percent of the students answered that they had used the library more than twice a month. Nevertheless the number of students consulting the catalogue with the same frequency was only 220, or a n.0, pproximately 58 percent. Those who used the library most tended to use the catalogue more than those who rarely came to the library. 2. Those who had been shown how to use their own catalogue were only 32.5percent of which the students found the instruction sufficient for them to be able to use the catalogue were only 37.5 percent. In particular, they stated that instructions by printed materials and/or library orientation were so poor that they didn't give much help in using the catalogue. This problem makes many libraries to review their own method of instruction in order to encourage patrons to use the catalogue more effectively. 3. Most of the students consulted the catalogue in order to locate library materials. Known-item searches and subject searches were 84 and 16 percent respectively. While 70.5 percent of the students used the author-title catalogue without any difficulties, only 35.5 percent of those stated that using the classed catalogue was easy. 4. It was surprising that the number of students using title access in the search was far greater than that of students using author access. In contrast with this, other studies conducted by many earlier overseas investigators revealed that the great majority of patrons tended to use the latter first. Therefore, we should put more emphasis on the title entries in the catalogue itself as well as cataloging rules. 5. Most useful bibliographic elements in the entry were author, title, call number, date and publisher whereas edition, series statement and the location of publisher were rarely used compared with the other elements. Content note was the most desirable element in the entry to be involved, for many catalogers were used not to describe it on the note area. 6. The chief reason given for not using the catalogue was "I can manage without it" with "It's difficult to understand contents of the card entry." The other one was "It's useless to search materials by the catalogue because I've failed so many times to obtain them out of the stock." In response to this, circulation and acquisition system should be improved not to make such complaints any more.

  • PDF

Growth of Zn0.4Fe2.6O4 Thin Films using Pulsed Laser Deposition and their Crystal Structural and Magnetic Properties (Pulsed Laser Deposition을 이용한 Zn0.4Fe2.6O4 박막의 합성과 그 결정성 및 자기적 특성의 연구)

  • Jang, A.N.;Song, J.H.;Park, C.Y.
    • Journal of the Korean Magnetics Society
    • /
    • v.21 no.3
    • /
    • pp.88-92
    • /
    • 2011
  • We grew $Zn_{0.4}Fe_{2.6}O_4$ thin films using Pulsed Laser Deposition and studied their crystal structure and magnetical characteristics as a function of growth temperature ($T_g$). For the film with $T_g=300^{\circ}C$, X-ray reflections from ${\alpha}-Fe_2O_3$ and ZnO were observed. However, when $T_g$ was increased from 300 to $500^{\circ}C$, crystal structure of inverse spinel was stabilized with the crystal orientation of $Zn_{0.4}Fe_{2.6}O_4(111)/Al_2O_3(0001)$ without any detection of ${\alpha}-Fe_2O_3$ and ZnO phases. The surface morphology shows flattening behavior with increasing $T_g$ from 300 to $500^{\circ}C$. These observations indicate that Zn is substituted into tetrahedron A-site of the inverse-spinel $Fe_3O_4$. M-H curves exhibit clear ferromagnetism for the sample with $T_g=500^{\circ}C$ whereas no ferromagnetism is observed for the film with $T_g=300^{\circ}C$.