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Our studies evidence an anisotropic magnetic order below $T_N = 32$~K. Susceptibility data in small fields of about 1~T reveal an antiferromagnetic (AFM) order for $H perp c$, whereas for $H parallel c$ the data are reminiscent of a field-induced ferromagnetic (FM) structure. At low temperatures and for $H perp c$, the field-dependent magnetization and AC susceptibility data evidence a metamagnetic transition at $H^+ = 5$~T, which is absent for $H parallel c$. We assign this to a transition from a planar cycloidal spin structure at low fields to a planar fan-like arrangement above $H^+$. A fully FM polarized state is obtained above the saturation field of $H_{perp S} = 23.7$~T at 2~K with a magnetization of $M_s = 2.8$~$mu_{rm B}{rm /Cr}$. For $H parallel c$, $M(H)$ monotonously increases and saturates at the same $M_s$ value at $H_{parallel S} = 25.1$~T at 4.2~K. Above $T_N $, the magnetic susceptibility and specific heat indicate signatures of two dimensional (2D) frustration related to the presence of planar ferromagnetic and antiferromagnetic exchange interactions. We found a pronounced nearly isotropic maximum in both properties at about $T^* = 45$~K, which is a clear fingerprint of short-range correlations and emergent spin fluctuations. Calculations based on a planar 2D Heisenberg model support our experimental findings and suggest a predominant FM exchange among nearest and AFM exchange among third-nearest neighbors. Only a minor contribution might be assigned to the antisymmetric Dzyaloshinskii-Moriya interaction possible related to the non-centrosymmetric polar space group $R3m$. Due to these competing interactions, the magnetism in AgCrSe$_{2}$, in contrast to the oxygen based delafossites, can be tuned by relatively small, experimentally accessible, magnetic fields, allowing us to establish the complete anisotropic magnetic $H-T$ phase diagram in detail.
Recently, several putative quantum spin liquid (QSL) states were discovered in ${tilde S} = 1/2$ rare-earth based triangular-lattice antiferromagnets (TLAF) with the delafossite structure. A way to clarify the origin of the QSL state in these systems
The crystal structure and magnetic correlations in triangular antiferromagnet FeGa$_2$S$_4$ are studied by x-ray diffraction, magnetic susceptibility, neutron diffraction and neutron inelastic scattering. We report significant mixing at the cation si
PbFe$_{1/2}$Ta$_{1/2}$O$_{3}$ (PFT) belongs to the family of PbB$_{x}$B$_{1-x}$O$_{3}$ which have inherent chemical disorder at the B-site. Due to this disorder, a complex magnetic phase diagram is expected in the material. In this paper, we report e
The magnetic phases of a triangular-lattice antiferromagnet, CuCrO$_2$, were investigated in magnetic fields along to the $c$ axis, $H$ // [001], up to 120 T. Faraday rotation and magneto-absorption spectroscopy were used to unveil the rich physics o
We present a single crystal neutron diffraction study of the magnetic short-range correlations in Tb$_5$Ge$_4$ which orders antiferromagnetically below the Neel temperature $T_N$ $approx$ 92 K. Strong diffuse scattering arising from magnetic short-ra