μ+SR study on ferromagnetic hollandite K2Cr8O

Abstract

The magnetism of a quasi-one-dimensional ferromagnetic (FM) compound, K 2 Cr 8 O 16 , has been investigated by muon-spin rotation and relaxation (μ + SR) using a powder sample in the temperature range between 2 and 225 K. Below T c = 163 K, muon-spin precession signals were clearly observed in the zero-field spectrum, indicating the formation of static FM order. It was also found that the internal field does not change drastically at the metal-to-insulator transition temperature, T MI ∼ 100 K. Electrostatic potential calculations and dipole field calculations suggested that FM order is not parallel to the [100], [010], [001], and [110] directions but likely parallel to the [101], [011], and/or [111] directions. A very similar result was obtained for a related compound, Rb 2 Cr 8 O 16 , while itsT c is 254 K.

μ+SR Study of K2Cr8O16 Under Hydrostatic Pressure

“…1 to the µ + SR time spectrum: f 1 = 45.1, f 2 = 78.3, f 3 = 82.1 and f 4 = 111.9 MHz where f n is proportional to the internal magnetic field. These frequencies are slightly different from the previous ambient µ + SR measurement [11] The time spectrum for p = 0 kbar and p = 25 kbar is shown in Figs. 2 (a) and 2 (c) where the fit using Eq.…”

“…Magnetization measurements reported a Curie temperature T C = 180 K and temperature dependence of the electrical resistivity suggested a MIT temperature T MIT = 95 K at ambient pressure [8,10]. The previous µ + SR study of the compound [11] obtained a T C ≃ 168 K by weak-transverse field (wTF) measurements. The difference between the T C values obtained from magnetization measurements and µ + SR experi-ments can be attributed to the fact that the µ + SR technique allows for measurements in very low (or even zero) externally applied magnetic fields.…”

Magnetism of the A -site ordered perovskites CaCu3Cr4O12 and L

“…Nevertheless, μ + SR measurements demonstrated the presence of static magnetic order in LaCu 3 Cr 4 O 12 [4]. This clearly indicates the importance of μ + SR for studying magnetic ground states of complex oxides, as already shown for other chromium compounds [12][13][14][15][16][17][18][19].…”

Na-ion dynamics in Quasi-1D compound NaV2O4

“…In order to investigate the diffusive properties of Na-ions in the NaV 2 O 4 compound we have used our previously presented µ + SR technique for studying solid state ion diffusion in battery related materials [16,17]. In similarity to our previous extensive measurements of both Li-ion [16,18,19,20,21] and Na-ion [17] diffusion, a series of ZF, wTF = 30 G as well as LF = 5 G and 10 G µ + SR spectra were acquired in the temperature range between 140 and 500 K [see Fig. 2(a-b)].…”