All-optical Helicity-Independent Switching State Diagram in 
Gd
-
Fe
-
Co
 Alloys

Jiaqi Wei; Boyu Zhang; Michel Hehn; Wei Zhang; Gregory Malinowski; Yong Xu; Weisheng Zhao; Stéphane Mangin

doi:10.1103/physrevapplied.15.054065

All-optical Helicity-Independent Switching State Diagram in Gd - Fe - Co Alloys

Physical Review Applied ◽

10.1103/physrevapplied.15.054065 ◽

2021 ◽

Vol 15 (5) ◽

Author(s):

Jiaqi Wei ◽

Boyu Zhang ◽

Michel Hehn ◽

Wei Zhang ◽

Gregory Malinowski ◽

...

Keyword(s):

State Diagram ◽

All Optical ◽

Co Alloys ◽

Switching State

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Lorentz microscopy study of magnetic domain walls in Fe-Cr-Co alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109458 ◽

1978 ◽

Vol 36 (1) ◽

pp. 462-463

Author(s):

Yalcin Belli

Keyword(s):

Domain Walls ◽

Magnetic Domain ◽

Microscopy Study ◽

Ferromagnetic Phase ◽

Stable Phase ◽

Magnetic Domains ◽

Lorentz Microscopy ◽

Magnetic Hardening ◽

Electron Microscopes ◽

Co Alloys

Fe-Cr-Co alloys have great technological potential to replace Alnico alloys as hard magnets. The relationship between the microstructures and the magnetic properties has been recently established for some of these alloys. The magnetic hardening has been attributed to the decomposition of the high temperature stable phase (α) into an elongated Fe-rich ferromagnetic phase (α1) and a weakly magnetic or non-magnetic Cr-rich phase (α2). The relationships between magnetic domains and domain walls and these different phases are yet to be understood. The TEM has been used to ascertain the mechanism of magnetic hardening for the first time in these alloys. The present paper describes the magnetic domain structure and the magnetization reversal processes in some of these multiphase materials. Microstructures to change properties resulting from, (i) isothermal aging, (ii) thermomagnetic treatment (TMT) and (iii) TMT + stepaging have been chosen for this investigation. The Jem-7A and Philips EM-301 transmission electron microscopes operating at 100 kV have been used for the Lorentz microscopy study of the magnetic domains and their interactions with the finely dispersed precipitate phases.

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Correlation analysis of radiation damage

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108210 ◽

1978 ◽

Vol 36 (1) ◽

pp. 214-215

Author(s):

R. Hegerl ◽

A. Feltynowski ◽

B. Grill

Keyword(s):

Electron Microscopy ◽

Independent Random Variables ◽

Optical Parameters ◽

Bright Field Image ◽

Bright Field ◽

Expectation Value ◽

All Optical ◽

Image Element ◽

Stochastic Series ◽

The Common

Till now correlation functions have been used in electron microscopy for two purposes: a) to find the common origin of two micrographs representing the same object, b) to check the optical parameters e. g. the focus. There is a third possibility of application, if all optical parameters are constant during a series of exposures. In this case all differences between the micrographs can only be caused by different noise distributions and by modifications of the object induced by radiation.Because of the electron noise, a discrete bright field image can be considered as a stochastic series Pm,where i denotes the number of the image and m (m = 1,.., M) the image element. Assuming a stable object, the expectation value of Pm would be Ηm for all images. The electron noise can be introduced by addition of stationary, mutual independent random variables nm with zero expectation and the variance. It is possible to treat the modifications of the object as a noise, too.

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