The low-field Hall effect and susceptibility of archetypal spin glasses-evidence for a second magnetic transition

Barnard, Robert; Ul-Haq, I.

doi:10.1088/0305-4608/18/6/026

Cited by 22 publications

(12 citation statements)

References 19 publications

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“…[4] concerning the sign ofD are valid, one hasC > 0 (with J sd > 0) andD > 0, which means ρ (chiral) xy is negative in canonical SG. This seems consistent with experiment [16,17]. The cusp-like singularity was observed there at least in the Hall resistivity [16,17], consistent with the present result.…”

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confidence: 93%

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Anomalous Hall Effect as a Probe of the Chiral Order in Spin Glasses

Kawamura

2003

Phys. Rev. Lett.

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Anomalous Hall effect arising from the noncoplanar spin configuration (chirality) is discussed as a probe of the chiral order in spin glasses. It is shown that the Hall coefficient yields direct information about the linear and nonlinear chiral susceptibilities of the spin sector, which has been hard to obtain experimentally from the standard magnetic measurements. Based on the chirality scenario of spin-glass transition, predictions are given on the behavior of the Hall resistivity of canonical spin glasses.For decades, spin glasses have been extensively studied as a prototype of "complex" systems characterized by both 'frustration' and 'randomness' [1]. Among a wide variety of spin-glass (SG) materials, most familiar and well-studied is perhaps the so-called canonical SG, a dilute noble metal/3d transition metal alloys. In canonical SG, the interaction between localized moments is the RKKY interaction which is mediated by conduction electrons via the s − d exchange coupling J sd . Oscillating nature of the RKKY interaction with distance, combined with spatially random arrangement of localized moments, gives rise to frustration and randomness. Since the RKKY interaction is isotropic in spin space, canonical SG like many other SGs is nearly isotropic in spin space, and is expected to be well modeled by the Heisenberg model. Weak magnetic anisotropy is mostly due to the Dzyaloshinski-Moriya (DM) interaction caused by the combined effect of the s − d coupling and the spinorbit interaction. Nearly isotropic character of the magnetic interaction in canonical SG is in apparent contrast to most of theoretical approaches which have been based on the Ising model describing the extremely anisotropic limit [1].Experimentally, it is now well established that typical SG magnets including canonical SG exhibit an equilibrium phase transition at a finite temperature and there exists a thermodynamic SG phase. True nature of the SG transition and of the SG ordered state, however, still remains elusive in spite of extensive studies [1].Although standard theories of the SG order invoke the Ising model as a minimal model, a scenario very different from the standard picture was proposed by the present author, which may be called a chirality scenario [2,3]. In this scenario, chirality, which is a multispin quantity representing the sense or the handedness of local noncoplanar structure of Heisenberg spins, plays an essential role. The local chirality may be defined for three neighboring Heisenberg spins by the scalar,The chirality defined above is often called a scalar chirality: It takes a nonzero value when the three spins span the noncoplanar configuration in spin space, whose sign representing the handedness of such noncoplanar spin configuration.The chirality scenario of SG transition consists of the two parts [2,3]: In a fully isotropic Heisenberg SG, it claims the occurrence of a novel chiral-glass ordered state in which only the chirality exhibits a glassy long-range order keeping the Heisenberg spin paramagnetic (spinchirali...

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supporting

confidence: 93%

“…This seems consistent with experiment [16,17]. The cusp-like singularity was observed there at least in the Hall resistivity [16,17], consistent with the present result.…”

supporting

confidence: 93%

Anomalous Hall Effect as a Probe of the Chiral Order in Spin Glasses

Kawamura

2003

Phys. Rev. Lett.

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“…The anomalous Hall resistivity varies proportional to the Fe spin magnetization, and its temperature dependence at low fields reveals a sharp peak near the freezing temperature T f . In agreement with direct magnetization measurements, the peak is washed out at higher magnetic fields [11,12].As illustrated in Fig. 1(b), the anomalous Hall effect is much weaker in a thin 2 at.…”

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confidence: 86%

Impurity Spin Magnetization of Thin Fe Doped Au Films

et al. 2000

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In order to probe the influence of the surface-induced anisotropy on the impurity spin magnetization, we measure the anomalous Hall effect in thin AuFe films at magnetic fields up to 15 T. The observed suppression of the anomalous Hall resistivity at low fields as well as the appearance of a minimum in the differential Hall resistivity at higher fields can be explained by our theoretical model, which takes into account the influence of a polycrystalline film structure on the surface-induced anisotropy. Our results imply that the apparent discrepancy between different experimental results for the size effects in dilute magnetic alloys can be linked to a different microstructure of the samples.

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“…2 differs significantly from that reported for data obtained at much higher fields [4,5]. Taking into account the demagnetizing effects both in the Hall and magnetization experiments, the total Hall coefficient may be decomposed as [6] R…”

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confidence: 72%