摘要:

Susceptibility measurements from dc to 500 kHz have been made on the linear coordination polymer, poly(cobalt n‐butylphosphinate). At high temperature the data conform to the classical Heisenberg antiferromagnetic chain with a mean field temperature of 28 K. Below about 20 K there is an excess susceptibility which saturates in modest fields. These results are described in terms of an antisymmetric exchange component which produces short‐range weak ferromagnetic order in the paramagnetic phase. At still lower temperature the ac susceptibility shows a loss component, even in zero applied field, which we ascribe to the motion of domain walls in the weak ferromagnetization.

ISSN:0021-8979    

DOI:10.1063/1.330961

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The effect of magnetic fields on the magnetic domain structure in thin iron films (∼200 A˚) has been studiedinsituby Lorentz microscopy in an electrostatic transmission electron microscope (TEM). The electrostatic instrument provides a specimen region free of magnetic fields. A special solenoid was placed in the specimen region, coaxial with the optic axis. By tilting the specimen holder a known in‐plane component of the field could be applied to the specimen. Studies were made with the in‐plane field applied parallel to and perpendicular to the domain walls.

ISSN:0021-8979    

DOI:10.1063/1.330962

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The Lorentz and Foucault methods have been used to study twisted domains in thin (∼200 A˚) iron films (made by evaporation) in an electrostatic transmission electron microscope (TEM). Twisted domains have been observed to occur spontaneously, as well as during and after the application of an in‐plane magnetic field. We have found that twisted domains consist of alternate sections separated by roughly 90° domain walls. Between these sections and the surrounding domain the wall is alternately 90° and 180°. The ripple structure in the micrographs provides further evidence as to the directions of magnetization. When Blochline‐crosstie pairs are present, they occur on the 180° walls but not on the 90° walls.

ISSN:0021-8979    

DOI:10.1063/1.330963

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

An analytic solution has been obtained for the magnetic field distribution and eddy current losses associated with an infinite array of regularly spaced 180° domain walls which are allowed to bow during their motion. Wall motion was constrained to satisfy a sinusoidal total flux boundary condition. The field solution was solved self‐consistently with the domain wall equation of motion. Calculated losses were always lowered relative to the plane wall case. Difficulties were encountered in the numerical iteration scheme as the degree of bowing increased. Using an approximation for the high bowing case, a physical instability occurred before bowing became too severe.

ISSN:0021-8979    

DOI:10.1063/1.330964

出版商:AIP    

年代:1982

数据来源: AIP