摘要:

A microwave contactless method is developed to measure the magnetoresistances of ZnSe and CdMnTe epitaxial layers grown by molecular beam epitaxy on semi-insulating GaAs substrates. The carrier concentrations and Hall mobilities are derived from the experimental data. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365841

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Intrinsic Josephson effect devices fromTl2Ba2CaCu2O8(Tl-2212) thin films were investigated. The device was produced by epitaxially growing a Tl-2212 thin film on aLaAlO3substrate with the surface cut at a small angle to theLaAlO3(001) plane, and by patterning a microbridge in the proper direction. TheI–Vcharacteristics of the microbridges exhibit large hysteresis at low temperatures, and the temperature dependence of the critical currentIc(T)is in good agreement with the theoretical Ambegaokar–Baratoff relation for superconductor–insulator–superconductor (SIS) junctions. TheI–Vcurves also show multibranches for longer microbridges. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365842

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Morphology changes and irreversible reorientation of the easy magnetization axis upon annealing of thin epitaxial fcc-iron films grown at 100 K on Cu(100) were studiedin situwith scanning tunneling microscopy and the magneto-optical Kerr effect. An irreversible spin reorientation from in-plane to out-of-plane is observed for 6 monolayers thick iron films annealed to 350 K. This change in magnetic anisotropy is accompanied by considerable smoothing of the iron film surface. Annealing to higher temperatures leads to a strong increase of the coercive field by up to a factor of 6. The surfaces of these films are atomically flat and display some scattered needle-like protrusions and dislocation lines. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365581

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The evolutionary process of the anisotropic magnetoresistance from the positive to the negative by changing the field direction was observed in magnetic thin films of Ni-Co, Ni-Fe and Co. Various peculiar magnetoresistance-field curves occur, that can be understood by a model based on the superposition of the positive and negative magnetoresistance with different amplitudes and phases. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365843

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Atomic scale simulations are performed for the ion bombardment induced roughening of the amorphous diamond films, when the films are deposited by using kiloelectronvolt mass separated ion beams operated in the upper limit of practical deposition energies up to 20 keV. The results show that the roughness due to sputtering erosion is by a factor of 3 to 4 larger than roughness observed in experiments. The experimentally observed roughness is obtained only when moderate surface relaxation within the distance of next nearest neighbors is included in the simulations. The results suggest that atomic scale relaxation of sputtering induced topography occurs during the deposition. ©1997 American Institute of Physics. 

ISSN:0021-8979    

DOI:10.1063/1.365844

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

J. D. Guo &etal; [J. Appl. Phys.80, 1623 (1996)] have studied the thermal stability of Ni on GaN and have deduced by x-ray diffraction measurements that new phases form at the interface between Ni and GaN. This determination, based solely on x-ray diffraction data, is ambiguous, as the peaks assigned to theGa4Ni3and Ni–N phases can also be attributed to substrate related x-ray peaks. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365845

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The phase equilibria of the Ga–Ni–As ternary system, especially in its upper part, has given rise to much controversy. An attempt to clarify this situation is given in this comment. We show that the re-examined diagram proposed by Ingerly &etal; [J. Appl. Phys.80, 543 (1996)] is not right owing to a much too limited number of synthesized samples, and that this diagram cannot rationalize the complex solid-state interdiffusion which occurs in the Ni/GaAs contacts. We confirm the occurrence of ordered ternary phases which crystallize in hexagonal superlatticesa&sqrt;3,3cand2a,4cderivative from the NiAs-type structure. Finally, we point out that these superlattices index successfully all the extra lines of the x-ray diffraction pattern that Ingerly &etal; were unable to explain. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365582

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We reply to the comment by Guerin and Guvarc’h concerning the phase equilibria of the Ga–Ni–As ternary system. We refute their position that the quench rate of the phase diagram samples is not important and that the solid-state phase equilibria of the Ga–Ni–As system does not change significantly between the temperatures of 25 and 800 °C. It is also demonstrated that the occurrence of ordered superlattice structures is not inconsistent with our work. We conclude that an adequate number of samples were prepared in our study to justify the modifications proposed to the Ga–Ni–As isothermal section and it is an accurate representation of the phase equilibria at 600 °C. ©1997 American Institute of Physics.

ISSN:0021-8979    

DOI:10.1063/1.365846

出版商:AIP    

年代:1997

数据来源: AIP