Magnetic properties of the CoxZn1-xO (x=0.20, 0.86, 0.92) films and its tunnel magnetoresistance

被引：1

作者：

Wang, Feng ^{[1
]}

Wan, Wenfeng ^{[1
]}

Chen, Lu ^{[2
]}

Laako, M. J. O. ^{[2
]}

机构：

[1] Quanzhou Normal Univ, Phys & Informat Engn Sch, Quanzhou 362000, Peoples R China

[2] Univ Oulu, Dept Phys, Oulu 90014, Finland

来源：

MATERIALS RESEARCH EXPRESS | 2015年 / 2卷 / 12期

基金：

芬兰科学院;

关键词：

CoZnO; magnetic semiconductor; magnetic tunnel junctions; anomalous Hall effects; THIN-FILMS; FERROMAGNETISM; SEMICONDUCTORS; OXIDE;

D O I：

10.1088/2053-1591/2/12/126102

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

CoxZn1-xO(X = 0.20, 0.86, 0.92) films were synthesized using the radio frequency (RF) cosputtering method. Though the same synthesis method was used, these samples exhibited different structures and magnetic properties. The Co0.20Zn0.80O film sample was crystalline, but its magnetic property was antiferromagnetism. Amorphous phase, room temperature ferromagnetism and anomalous Hall effect were shown in the sputtered and annealed Co0.86Zn0.14O and Co0.92Zn0.08O samples. Through x-ray photoelectron spectroscopy (XPS), the ferromagnetism of the high Co content amorphous films originates from metallic Co. The antiferromagnetism of Co0.20Zn0.80O crystalline film can be explained by an indirect-exchange interaction model. The electric conductivity is interpreted with the spin-dependent variable-range hopping model at low temperature. A tunneling magnetoresistance (TMR) ratio of 16.4% was observed at 77 Kin Co(40 nm)/ZnO(4 nm)/ Co0.92Zn0.08O(75 nm) magnetic tunnel junctions (MTJs). The MTJs can resist up to room temperature with the TMR ratio of 1.6% at 10 kOe.

引用

页数：8

共 44 条

[1] ANTIFERROMAGNETISM - THEORY OF SUPEREXCHANGE INTERACTION [J].

ANDERSON, PW .

PHYSICAL REVIEW, 1950, 79 (02) :350-356

[2]

[Anonymous], 2005, INTRO SOLID STATE PH

[3] Molecular beam epitaxial growth and properties of CoFe2O4 on MgO(001) [J].

Chambers, SA ;

Farrow, RFC ;

Maat, S ;

Toney, MF ;

Folks, L ;

Catalano, JG ;

Trainor, TP ;

Brown, GE .

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 2002, 246 (1-2) :124-139

[4] Ferromagnetism in doped thin-film oxide and nitride semiconductors and dielectrics [J].

Chambers, Scott A. .

SURFACE SCIENCE REPORTS, 2006, 61 (08) :345-381

[5] LSDA+U versus LSDA:: Towards a better description of the magnetic nearest-neighbor exchange coupling in Co- and Mn-doped ZnO -: art. no. 134418 [J].

Chanier, T ;

Sargolzaei, M ;

Opahle, I ;

Hayn, R ;

Koepernik, K .

PHYSICAL REVIEW B, 2006, 73 (13)

[6] Zener model description of ferromagnetism in zinc-blende magnetic semiconductors [J].

Dietl, T ;

Ohno, H ;

Matsukura, F ;

Cibert, J ;

Ferrand, D .

SCIENCE, 2000, 287 (5455) :1019-1022

[7]

Editorial staff, 2005, SCIENCE, V309, P82

[8] COULOMB GAP AND LOW-TEMPERATURE CONDUCTIVITY OF DISORDERED SYSTEMS [J].

EFROS, AL ;

SHKLOVSKII, BI .

JOURNAL OF PHYSICS C-SOLID STATE PHYSICS, 1975, 8 (04) :L49-L51

[9] Effect of Co doping on the structural, optical and magnetic properties of ZnO nanoparticles [J].

Hays, J. ;

Reddy, K. M. ;

Graces, N. Y. ;

Engelhard, M. H. ;

Shutthanandan, V. ;

Luo, M. ;

Xu, C. ;

Giles, N. C. ;

Wang, C. ;

Thevuthasan, S. ;

Punnoose, A. .

JOURNAL OF PHYSICS-CONDENSED MATTER, 2007, 19 (26)

[10] Role of grain boundary and grain defects on ferromagnetism in Co:ZnO films [J].

Hsu, H. S. ;

Huang, J. C. A. ;

Chen, S. F. ;

Liu, C. P. .

APPLIED PHYSICS LETTERS, 2007, 90 (10)

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