Evidence of symmetry lowering in antiferromagnetic metal TmB12 with dynamic charge stripes

Abstract

Abstract Precise angle-resolved magnetoresistance (ARMR) and magnetization measurements have revealed (i) strong charge transport and magnetic anisotropy and (ii) emergence of a huge number of magnetic phases in the ground state of isotopically 11B-enriched single crystals of TmB12 antiferromagnetic (AF) metal with fcc crystal structure and dynamic charge stripes. We analyze for the first time the angular H–φ phase diagrams of AF state of Tm11B12 reconstructed from experimental ARMR and magnetization data arguing that the symmetry lowering leads to the appearance of several radial phase boundaries between different phases in the AF state. It is proposed that the suppression of the indirect Ruderman–Kittel–Kasuya–Yosida (RKKY) exchange along ⟨110⟩ directions between nearest neighboring magnetic moments of Tm3+ ions and subsequent redistribution of conduction electrons to quantum fluctuations of the electron density (dynamic stripes) are the main factors responsible for the anisotropy. Essential (more than 25% at T = 2 K) anisotropy of the Neel field in the (110) plane was found in Tm11B12 unlike to isotropic AF–P boundary in the H–φ phase diagrams of Ho11B12. Magnetoresistance components are discussed in terms of charge carrier scattering on the spin density wave, itinerant ferromagnetic nano-domains and on-site Tm3+ spin fluctuations.