Tunable exchange bias in dilute magnetic alloys – chiral spin glasses

Heinrich, Matthias; Mathieu, Roland; Nordblad, Per

doi:10.1038/srep19964

Cited by 18 publications

(11 citation statements)

References 30 publications

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“…Only a fraction of the spin folds is repolarized upon a reverse field sweep, resulting in the shifted hysteresis loop. This explanation has similarities to what has been proposed in canonical spin glasses, 42 , 44 but with a key distinction. In the case of canonical spin glasses, the first field-intercept of the hysteresis loop is independent of the annealing field, which has been interpreted as arising from the introduction of a rigid chiral spin texture in the material, even in the presence of a small magnetic field.…”

Section: Discussionsupporting

confidence: 82%

Exchange Bias in a Layered Metal–Organic Topological Spin Glass

et al. 2021

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The discovery of conductive and magnetic two-dimensional (2D) materials is critical for the development of next generation spintronics devices. Coordination chemistry in particular represents a highly versatile, though underutilized, route toward the synthesis of such materials with designer lattices. Here, we report the synthesis of a conductive, layered 2D metal–organic kagome lattice, Mn 3 (C 6 S 6 ), using mild solution-phase chemistry. Strong geometric spin frustration in this system mediates spin freezing at low temperatures, which results in glassy magnetic dynamics consistent with a rare geometrically frustrated (topological) spin glass. Notably, we show that this geometric frustration engenders a large, tunable exchange bias of 1625 Oe in Mn 3 (C 6 S 6 ), providing the first example of exchange bias in a coordination solid or a topological spin glass. Exchange bias is a critical component in a number of spintronics applications, but it is difficult to rationally tune, as it typically arises due to structural disorder. This work outlines a new strategy for engineering exchange bias systems using single-phase, crystalline lattices. More generally, these results demonstrate the potential utility of geometric frustration in the design of new nanoscale spintronic materials.

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Section: Discussionsupporting

confidence: 82%

Exchange Bias in a Layered Metal–Organic Topological Spin Glass

et al. 2021

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“…Only a fraction of the spin folds is repolarized upon a reverse field sweep, resulting in the shifted hysteresis loop. This explanation has similarities to what has been proposed in canonical spin glasses 39 , but with a key distinction. In the case of canonical spin glasses, the first field-intercept of the hysteresis loop is independent of the annealing field, which has been interpreted as arising from the introduction of a rigid chiral spin texture in the material, even in the presence of a small magnetic field.…”

Section: Magnetic Propertiessupporting

confidence: 81%

“…Given that structural and magnetic data do not support disorder in Mn 3 (C 6 S 6 ), we propose an alternative explanation for the exchange bias that invokes an interplay of antisymmetric exchange and magnetic field-mediated chiral induction of the spin texture 38,39 . Field-dependent chiral magnetic order has been theoretically proposed 40 and experimentally verified 29 in Heisenberg kagome antiferromagnets, in particular in potassium iron jarosite, a spin congener of Mn 3 (C 6 S 6 ).…”

Section: Magnetic Propertiesmentioning

confidence: 83%

Exchange Bias in a Layered Metal–Organic Topological Spin Glass

Murphy

Darago²,

Ziebel³

et al. 2020

Preprint

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The discovery of conductive and magnetic two-dimensional (2D) materials is critical for the development of next generation spintronics devices. Coordination chemistry in particular represents a highly versatile, though underutilized, route toward the synthesis of such materials with designer lattices. Here, we report the synthesis of a conductive, layered 2D metal–organic kagome lattice, Mn3(C6S6), using mild solution-phase chemistry. Strong geometric spin frustration in this system mediates spin freezing at low temperatures, which results in glassy magnetic behavior consistent with a geometrically frustrated (topological) spin glass. Notably, the material exhibits a large exchange bias of 1625 Oe, providing the first example of exchange bias in a coordination solid or a topological spin glass. More generally, these results demonstrate the potential utility of geometrically frustrated lattices in the design of new nanoscale spintronic materials.

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“…In [46], the EB effect was found to occur under zero-field cooling. In [47][48][49][50][51][52][53][54], the EB effect was reported in AFM/SG systems. In [49,50,55], a spin glass (SG), such as disorder, was suggested to occur at the FM-AFM interface.…”

Section: Magnetic Measurements Of the S1 And S2 Core-shell Nanoparticlesmentioning

confidence: 99%

Tailoring Interfacial Exchange Anisotropy in Hard–Soft Core-Shell Ferrite Nanoparticles for Magnetic Hyperthermia Applications

et al. 2022

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Magnetically hard–soft core-shell ferrite nanoparticles are synthesized using an organometallic decomposition method through seed-mediated growth. Two sets of core-shell nanoparticles (S1 and S2) with different shell (Fe3O4) thicknesses and similar core (CoFe2O4) sizes are obtained by varying the initial quantities of seed nanoparticles of size 6.0 ± 1.0 nm. The nanoparticles synthesized have average sizes of 9.5 ± 1.1 (S1) and 12.2 ± 1.7 (S2) nm with corresponding shell thicknesses of 3.5 and 6.1 nm. Magnetic properties are investigated under field-cooled and zero-field-cooled conditions at several temperatures and field cooling values. Magnetic heating efficiency for magnetic hyperthermia applications is investigated by measuring the specific absorption rate (SAR) in alternating magnetic fields at several field strengths and frequencies. The exchange bias is found to have a nonmonotonic and oscillatory relationship with temperature at all fields. SAR values of both core-shell samples are found to be considerably larger than that of the single-phase bare core particles. The effective anisotropy and SAR values are found to be larger in S2 than those in S1. However, the saturation magnetization displays the opposite behavior. These results are attributed to the occurrence of spin-glass regions at the core-shell interface of different amounts in the two samples. The novel outcome is that the interfacial exchange anisotropy of core-shell nanoparticles can be tailored to produce large effective magnetic anisotropy and thus large SAR values.

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Tunable exchange bias in dilute magnetic alloys – chiral spin glasses

Cited by 18 publications

References 30 publications

Exchange Bias in a Layered Metal–Organic Topological Spin Glass

Exchange Bias in a Layered Metal–Organic Topological Spin Glass

Exchange Bias in a Layered Metal–Organic Topological Spin Glass

Tailoring Interfacial Exchange Anisotropy in Hard–Soft Core-Shell Ferrite Nanoparticles for Magnetic Hyperthermia Applications

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