Related Experiment Video
Updated: May 24, 2026
07:42
Optimizing Magnetic Force Microscopy Resolution and Sensitivity to Visualize Nanoscale Magnetic Domains
Published on: July 20, 2022
Non-Kondo mechanism for resistivity minimum in spin ice conduction systems
Masafumi Udagawa1, Hiroaki Ishizuka, Yukitoshi Motome
1Department of Applied Physics, University of Tokyo, Tokyo, Japan.
Physical Review Letters
|March 10, 2012
Summary
We discovered a new resistivity minimum mechanism in metals, distinct from the Kondo effect. It involves elastic electron scattering by frustrated spin correlations, explaining experimental data in iridium pyrochlores.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- The Kondo effect explains resistivity minima due to spin-flip scattering.
- Geometrical frustration in materials can lead to complex magnetic behaviors.
- Metallic pyrochlores, like iridium oxides, exhibit unusual electronic properties.
Purpose of the Study:
- To present a novel mechanism for resistivity minima.
- To differentiate this mechanism from the established Kondo effect.
- To explain experimental observations in metallic Ir pyrochlores.
Main Methods:
- Utilizing cellular dynamical mean-field theory (CDMFT).
- Modeling a spin-ice-type Kondo lattice on a pyrochlore lattice.
- Comparing theoretical predictions with experimental data.
Main Results:
- A resistivity minimum mechanism driven by elastic scattering from spin correlations.
- Spin correlations evolve uniquely under geometrical frustration with decreasing temperature.
- Model successfully reproduces peculiar temperature dependencies of resistivity, specific heat, and magnetic susceptibility.
Conclusions:
- The proposed non-Kondo mechanism accurately describes resistivity minima in certain materials.
- Geometrical frustration plays a crucial role in the observed electronic properties.
- This work provides a new framework for understanding electron-impurity interactions in frustrated magnetic systems.
Related Concept Videos
01:24Superconductor
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a superconductor. In 1911, Heike Kamerlingh Onnes of Leiden University, a Dutch physicist, observed a relation between the temperature and the resistance of the element mercury. The mercury sample was then cooled in liquid helium to study the linear dependence of resistance on temperature. It was observed that, as the temperature decreased, the...
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
01:17Theory of Metallic Conduction
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
01:26Diamagnetism
Materials consisting of paired electrons have zero net magnetic moments. However, when these materials are placed under an external magnetic field, the moments opposite to the field are induced. Such materials are called diamagnets. Diamagnetism is the response of the diamagnets when placed in an external magnetic field.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
01:13Electrical Conductivity
In perfect conductors, the electric field inside is always zero due to the abundance of free electrons, which nullify any field by flowing. As a result, any residual charge resides on the surface.
In a practical conductor, an applied electric field may be sustained, causing a flow of electrons, which produce a current. The differential form of the current, the current density, is related to the electric field.
More generally, it is related to the force per unit charge, which involves the...
In a practical conductor, an applied electric field may be sustained, causing a flow of electrons, which produce a current. The differential form of the current, the current density, is related to the electric field.
More generally, it is related to the force per unit charge, which involves the...
01:14Atomic Nuclei: Nuclear Spin State Population Distribution
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.