Influence of Concentration Fluctuations on Relaxation Processes in Spin Glasses
Using the unique combination of atomically resolved atom probe tomography (APT) and volume averaged neutron (resonance) spin echo (NRSE and NSE) experiments, the influence of nano-scaled clusters on the spin relaxation in spin glasses was studied. For this purpose, the phase transition from the para...
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doaj-d5983720457049d4be87cd6b21f8e2982020-11-25T00:37:30ZengMDPI AGQuantum Beam Science2412-382X2018-11-01242610.3390/qubs2040026qubs2040026Influence of Concentration Fluctuations on Relaxation Processes in Spin GlassesJulia N. Wagner0Wolfgang Häußler1Olaf Holderer2Andreas Bauer3Stephen M. Shapiro4Peter Böni5Physik-Department E21, Technische Universität München, 85747 Garching, GermanyPhysik-Department E21, Technische Universität München, 85747 Garching, GermanyForschungszentrum Jülich GmbH, JCNS Outstation at MLZ, Lichtenbergstr. 1, 85747 Garching, GermanyPhysik-Department E21, Technische Universität München, 85747 Garching, GermanyBrookhaven National Laboratory, Department of Physics, Upton, NY 11973, USAPhysik-Department E21, Technische Universität München, 85747 Garching, GermanyUsing the unique combination of atomically resolved atom probe tomography (APT) and volume averaged neutron (resonance) spin echo (NRSE and NSE) experiments, the influence of nano-scaled clusters on the spin relaxation in spin glasses was studied. For this purpose, the phase transition from the paramagnetic phase to the spin glass phase in an Fe-Cr spin glass with a composition of Fe<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mrow> <mn>17.8</mn> </mrow> </msub> </semantics> </math> </inline-formula>Cr<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mrow> <mn>82.2</mn> </mrow> </msub> </semantics> </math> </inline-formula> was studied in detail by means of NRSE. The microstructure was characterised by APT measurements, which show local concentration fluctuations of Fe and Cr on a length scale of 2 to 5 nm, which lead (i) to the coexistence of ferro- and anti-ferromagnetic clusters and (ii) a change of the magnetic properties of the whole sample, even in the spin glass phase, where spins are supposed to be randomly frozen. We show that a generalized spin glass relaxation function, which was successfully used to describe the phase transition in diluted spin glasses, can also be used for fitting the spin dynamics in spin glasses with significant concentration fluctuations.https://www.mdpi.com/2412-382X/2/4/26spin glassesdisordered systemsmagnetismneutron spin echo |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Julia N. Wagner Wolfgang Häußler Olaf Holderer Andreas Bauer Stephen M. Shapiro Peter Böni |
spellingShingle |
Julia N. Wagner Wolfgang Häußler Olaf Holderer Andreas Bauer Stephen M. Shapiro Peter Böni Influence of Concentration Fluctuations on Relaxation Processes in Spin Glasses Quantum Beam Science spin glasses disordered systems magnetism neutron spin echo |
author_facet |
Julia N. Wagner Wolfgang Häußler Olaf Holderer Andreas Bauer Stephen M. Shapiro Peter Böni |
author_sort |
Julia N. Wagner |
title |
Influence of Concentration Fluctuations on Relaxation Processes in Spin Glasses |
title_short |
Influence of Concentration Fluctuations on Relaxation Processes in Spin Glasses |
title_full |
Influence of Concentration Fluctuations on Relaxation Processes in Spin Glasses |
title_fullStr |
Influence of Concentration Fluctuations on Relaxation Processes in Spin Glasses |
title_full_unstemmed |
Influence of Concentration Fluctuations on Relaxation Processes in Spin Glasses |
title_sort |
influence of concentration fluctuations on relaxation processes in spin glasses |
publisher |
MDPI AG |
series |
Quantum Beam Science |
issn |
2412-382X |
publishDate |
2018-11-01 |
description |
Using the unique combination of atomically resolved atom probe tomography (APT) and volume averaged neutron (resonance) spin echo (NRSE and NSE) experiments, the influence of nano-scaled clusters on the spin relaxation in spin glasses was studied. For this purpose, the phase transition from the paramagnetic phase to the spin glass phase in an Fe-Cr spin glass with a composition of Fe<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mrow> <mn>17.8</mn> </mrow> </msub> </semantics> </math> </inline-formula>Cr<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mrow> <mn>82.2</mn> </mrow> </msub> </semantics> </math> </inline-formula> was studied in detail by means of NRSE. The microstructure was characterised by APT measurements, which show local concentration fluctuations of Fe and Cr on a length scale of 2 to 5 nm, which lead (i) to the coexistence of ferro- and anti-ferromagnetic clusters and (ii) a change of the magnetic properties of the whole sample, even in the spin glass phase, where spins are supposed to be randomly frozen. We show that a generalized spin glass relaxation function, which was successfully used to describe the phase transition in diluted spin glasses, can also be used for fitting the spin dynamics in spin glasses with significant concentration fluctuations. |
topic |
spin glasses disordered systems magnetism neutron spin echo |
url |
https://www.mdpi.com/2412-382X/2/4/26 |
work_keys_str_mv |
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1725301000441430016 |