We report the structural and magnetic properties of a new system LiRhMnO$_{ 4}$ (LRMO) through x-ray diffraction, bulk magnetization, heat capacity and $^{ 7}$Li nuclear magnetic resonance (NMR) measurements. LRMO crystallizes in the cubic space group $\mathit{ Fd}$$\bar{ 3}$$\mathit{ m}$. From the DC susceptibility data, we obtained the Curie-Weiss temperature $\mathrm{ \theta}_{ \mathrm{ CW}}$ = -26 K and Curie constant $\mathit{ C}$ = 1.79 Kcm$^{ 3}$/mol suggesting antiferromagnetic correlations among the magnetic Mn$^{ 4+}$ ions with an effective spin $\mathit{ S}$ = $\frac{ 3}{ 2}$. At $\mathit{ H}$ = 50 Oe, the field cooled and zero-field cooled magnetizations bifurcate at a freezing temperature, $T_{ f}$ = 4.45 K, which yields the frustration parameter $\mathit{ f=\frac{ \mid\theta_{ CW}\mid}{ T_{ f}}}>$5. AC susceptibility, shows a cusp-like peak at around $T_{ f}$, with the peak position shifting as a function of the driving frequency, confirming a spin-glass-like transition in LRMO. LRMO also shows typical spin-glass characteristics such as memory effect, aging effect and relaxation. In the heat capacity, there is no sharp anomaly down to 2 K indicative of long-range ordering. The field sweep $^{ 7}$Li NMR spectra show broadening with decreasing temperature without any spectral line shift. The $^{ 7}$Li NMR spin-lattice and spin-spin relaxation rates also show anomalies due to spin freezing near $T_{ f}$.
Categories: cond-mat.str-el