Low-Temperature Magnetoresistance Hysteresis in Granular Cr1-xFexO2: Slow Relaxation of Transport-Active Magnetic Configurations

E. Yu. Beliayev; V. A. Horielyi; I. G. Mirzoiev; V. V. Andrievskii

Home/Archive/arXiv

arXiv · 2607.25263

Low-Temperature Magnetoresistance Hysteresis in Granular Cr1-xFexO2: Slow Relaxation of Transport-Active Magnetic Configurations

E. Yu. Beliayev·V. A. Horielyi·I. G. Mirzoiev·V. V. Andrievskii

View original source ↗Read source document ↗Export metadata ↓

Abstract

Low-temperature magnetoresistance loops of compacted CrO2 powders become strongly nonmonotonic when electrical transport is dominated by a small number of spin-dependent intergranular tunnelling paths. We reanalyse previously reported data for undoped CrO2 and Fe-containing Cr1-xFexO2, focusing on additional branch crossings beyond the conventional low-field hysteresis. In the Fe-containing specimen, the resistance decreases, passes through a minimum, rises over an extended field interval, and then decreases again at higher field. This nonmonotonic hysteretic feature is strongly reduced when the magnetic-field sweep is slowed. Digitization of the three fastest sweeps shows that the field at which the resistance starts to recover shifts approximately linearly with sweep rate, corresponding to an effective magnetotransport relaxation time of about 3 s. This scale is attributed not to microscopic spin flips but to the slow evolution of local moment and domain configurations at the intergranular contacts dominating the current. The observations are consistent with conventional negative tunnelling magnetoresistance superimposed on a slower resistance-increasing contribution associated with transient local magnetic disorder. Fe increases coercivity and interfacial magnetic heterogeneity while reducing the overall negative magnetoresistance. The results support a transport-weighted magnetic-reconfiguration mechanism for the unusual hysteresis shape.

Explore related subjects

cond-mat.dis-nn

Keep this discovery

BibTeX RIS

E. Yu. Beliayev, V. A. Horielyi, I. G. Mirzoiev, V. V. Andrievskii. 2026-07-28. Low-Temperature Magnetoresistance Hysteresis in Granular Cr1-xFexO2: Slow Relaxation of Transport-Active Magnetic Configurations. https://arxiv.org/abs/2607.25263

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Irrationality Measure Controls Long-Wavelength Charge Fluctuations in Quasiperiodic Systems

Quasiperiodic order is characterized by irrational frequencies whose rational approximability known as irrationality measure defines distinct arithmetic classes. We establish that this arithmetic classification has direct physical consequences for long-wavelength charge fluctuations. In translation-covariant quasiperiodic systems, the infrared scaling of charge fluctuation is governed by the interplay between the irrationality exponent of irrational frequency and the large-harmonic decay of the hull charge profile: the latter determines the available charge weight, while the former controls how efficiently that weight is transferred to the infrared. Consequently, all algebraic irrational frequencies share the same arithmetic scaling, whereas exceptionally well-approximable transcendental frequencies can exhibit strongly enhanced infrared fluctuation scaling. We further prove that occupied states separated from the Fermi level by a gap stable throughout the hull contribute only an analytic infrared background, leaving the nontrivial scaling to near-Fermi states. Our results extend to general translation-covariant multi-frequency quasiperiodic systems.

cond-mat.dis-nn↗

arXiv2026

Curvature-Induced Geometric Universality in Non-Hermitian Anderson Transitions

In Euclidean space, universality classes of Anderson transitions are primarily determined by symmetry and spatial dimensionality. Here, we present evidence for a geometry-controlled universality class of non-Hermitian Anderson transitions on hyperbolic-like lattices. In this setting, critical behavior is influenced by the large-scale hyperbolic geometry, characterized by negative curvature, exponential volume growth, and a non-Euclidean notion of spatial scaling. Finite-size scaling of participation ratios across several distinct $ \{p,q\} $ tilings reveals one-parameter scaling collapses with a common critical exponent $ \nu\simeq1 $ within numerical accuracy. A complementary phenomenological coarse-grained Landau-Ginzburg analysis shows how exponential correlation-volume growth suppresses critical fluctuations, offering a rationale for the observed mean-field-like scaling. Our results suggest that spatial curvature can act as an additional organizing principle for Anderson-transition universality beyond the conventional dimensionality- and symmetry-based classification.

cond-mat.dis-nn↗

arXiv2026

Finite-rank multiplicative perturbations of rotationally invariant non-Hermitian random matrices

We study finite-rank multiplicative deformations of rotationally invariant non-Hermitian random matrices. More precisely, we consider models of the form $\mathbf{A}(\mathbf{I}+\mathbf{T})$, where $\mathbf{A}$ is a large rotationally invariant non-Hermitian random matrix, $\mathbf{T}$ is a finite-rank normal perturbation, and $\mathbf{I}$ denotes the identity matrix. We characterize the emergence of outlier eigenvalues, their fluctuations, and the associated eigenvector overlaps. Our results provide a multiplicative non-Hermitian counterpart to the classical Baik--Ben Arous--P\'ech\'e framework.

cond-mat.dis-nn↗