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Title: Non-Collinear Magnetism in Permalloy

Abstract

Permalloy is an important material in a wide variety of magnetic systems, most notably in GMR read-heads. However, despite this great interest its properties are not fully understood. For an in depth analysis of important physical properties as e.g. electric transport or magnetic anisotropy a detailed understanding of the distribution of magnetic moments on an atomic level is necessary. Using our first principles Locally Self-consistent Multiple Scattering (LSMS) method we calculate the magnetic ground state structure for a large super-cell model of Permalloy. Our code allows us to solve both the usual non-relativistic Schrdinger equation as well as the fully relativistic Dirac equation and to find the magnitude and direction of the magnetic moments at each atomic site. While the non-relativistic calculation yields a collinear ground state in accordance with previous calculations, we find the ground state for the fully relativistic calculation to be slightly non-collinear. We also investigate the influence of variations in the iron concentration on the distribution of magnetic moments.

Authors:
 [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Center for Computational Sciences
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
931297
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: 10th Joint MMM/Intermag Conference, Baltimore, MD, USA, 20070107, 20070111
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; DIRAC EQUATION; GROUND STATES; IRON; MAGNETIC MOMENTS; MAGNETISM; MULTIPLE SCATTERING; PERMALLOY; PHYSICAL PROPERTIES; TRANSPORT

Citation Formats

Eisenbach, Markus, Nicholson, Don M, and Stocks, George Malcolm. Non-Collinear Magnetism in Permalloy. United States: N. p., 2007. Web.
Eisenbach, Markus, Nicholson, Don M, & Stocks, George Malcolm. Non-Collinear Magnetism in Permalloy. United States.
Eisenbach, Markus, Nicholson, Don M, and Stocks, George Malcolm. Mon . "Non-Collinear Magnetism in Permalloy". United States. doi:.
@article{osti_931297,
title = {Non-Collinear Magnetism in Permalloy},
author = {Eisenbach, Markus and Nicholson, Don M and Stocks, George Malcolm},
abstractNote = {Permalloy is an important material in a wide variety of magnetic systems, most notably in GMR read-heads. However, despite this great interest its properties are not fully understood. For an in depth analysis of important physical properties as e.g. electric transport or magnetic anisotropy a detailed understanding of the distribution of magnetic moments on an atomic level is necessary. Using our first principles Locally Self-consistent Multiple Scattering (LSMS) method we calculate the magnetic ground state structure for a large super-cell model of Permalloy. Our code allows us to solve both the usual non-relativistic Schrdinger equation as well as the fully relativistic Dirac equation and to find the magnitude and direction of the magnetic moments at each atomic site. While the non-relativistic calculation yields a collinear ground state in accordance with previous calculations, we find the ground state for the fully relativistic calculation to be slightly non-collinear. We also investigate the influence of variations in the iron concentration on the distribution of magnetic moments.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

Conference:
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  • Permalloy is an important material in a wide variety of magnetic systems, most notably in GMR read-heads. However, despite this great interest its properties are not fully understood. For an in depth analysis of important physical properties as e.g. electric transport or magnetic anisotropy a detailed understanding of the distribution of magnetic moments on an atomic level is necessary. Using our first principles Locally Self-consistent Multiple Scattering (LSMS) method we calculate the magnetic ground state structure for a large super-cell model of Permalloy. Our code allows us to solve both the usual non-relativistic Schrdinger equation as well as the fullymore » relativistic Dirac equation and to find the magnitude and direction of the magnetic moments at each atomic site. While the non-relativistic calculation yields a collinear ground state in accordance with previous calculations, we find the ground state for the fully relativistic calculation to be slightly non-collinear. We also investigate the influence of variations in the iron concentration on the distribution of magnetic moments.« less
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  • The authors present an overview of the locally self-consistent multiple scattering (LSMS) method. The method is based on real space multiple scattering theory, is naturally highly parallel, and has been implemented on Intel Paragon parallel platforms within the Center for Computational Sciences at Oak Ridge National Laboratory. O(N)-scaling is demonstrated for unit cells as large as 1,000-atoms. They discuss in detail how the real space convergence properties of the method can be controlled by taking advantage of the stationary properties of a finite temperature Harris-Foulkes free energy functional. They show how the LSMS method can be combined with spin-dynamics tomore » treat non-collinear magnetic states of materials. They show some preliminary results for the ground state magnetic structure of FCC Fe{sub 0.65}Ni{sub 0.35} alloys that indicate the possible existence of non-collinear arranges of magnetic moments in this system.« less
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