摘要:

The &agr;-Fe/R2Fe14B-type exchange-coupled NdFeB nanocomposites with a coercivity(iHc) of more than 11 kOe and energy product,(BH)max,of more than 16 MGOe have been successfully obtained on melt spun(Nd0.95La0.05)7.5+xFebalCr2B10alloy powders, wherexranged from 3 to 3.5. It was found that a slight substitution of Cr for Fe suppresses the formation of theR2Fe23B3andFe3Bphases during crystallization and results in the formation of an &agr;-Fe/R2Fe14Bmixture. Increasing the total rare earth content was found to enhance the remanence, and theiHcof(Nd0.95La0.05)7.5+xFe80.5−xCr2B10ribbons was also increased drastically with increasing values ofx. ABrof 9.2–9.7 kG,iHcof 11.1–13.2 kOe, and(BH)maxof 16.5–18.0 MGOe have been obtained on(Nd0.95La0.05)7.5+xFe80.5−xCr2B10(x=3–3.5). ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121446

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The magneto-optically recorded marks with magnetic field modulation method were studied using spin-polarized scanning electron microscopy. We confirmed that marks with as short a length as 0.1 &mgr;m could be written repeatedly even with laser spot sizes about 1.2 &mgr;m. This mark length is less than16that of present commercial products. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120666

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We use molecular dynamics simulations to follow the dynamics of small two-dimensional Pt clusters on Pt(111) at 1000 K. While close-packedPt7heptamers are extremely stable structures, the addition of a single cluster vacancy or an on-top adatom immediately results in intracluster bond breaking, reconfigurations, rotations, the introduction of stacking faults, and greatly enhanced cluster diffusion rates. Mapping center-of-mass motion for total simulation times >145 ns revealed increases in cluster velocities by more than an order of magnitude with cluster migration occurring primarily by concerted motion and a novel diffusion mechanism involving double shearing of dimers/trimers. Contrary to some previous reports, edge-atom diffusion plays only a minor role. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120664

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Transient photocurrents are investigated in ferroelectric lead zirconate titanate (PZT) films illuminated by laser pulses in the spectral range of 340–380 nm. At low electric fields, the photocurrent is sensitive to the ferroelectric polarization state and changes sign upon the polarization switching. At higher fields, the polarization-independent current proportional to the applied electric field is dominant. The spectral dependence of polarization-dependent current is controlled by the excitation of charge carriers over the forbidden band of PZT having a maximum near 3.5 eV. Possible mechanisms of the observed effect are discussed and the possibilities of a nondestructive read out of polarization state in the ultraviolet spectral range are demonstrated. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120663

出版商:AIP    

年代:1998

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.120665

出版商:AIP    

年代:1998

数据来源: AIP