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

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 B-11-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-phi phase diagrams of AF state of (TmB12)-B-11 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 (TmB12)-B-11 unlike to isotropic AF-P boundary in the H-phi phase diagrams of (HoB12)-B-11. 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.

Automated summary

Precise angle-resolved magnetoresistance and magnetization measurements have revealed strong charge transport and magnetic anisotropy, as well as the emergence of multiple magnetic phases in the ground state of isotopically B-11-enriched TmB12 antiferromagnetic metal. The angular H-phi phase diagrams of the antiferromagnetic state were analyzed for the first time and it was proposed that the symmetry lowering is responsible for the appearance of radial phase boundaries between different phases. The Neel field in the (110) plane was found to have significant anisotropy in (TmB12)-B-11 unlike the isotropic AF-P boundary in (HoB12)-B-11.