Gd substitution induced incommensurate antiferromagnetism in B20 noncentrosymmetric CoSi.

Rare-earth element Gd doped CoSi, Co1-xGdxSi (x= 0.01), is investigated using x-ray diffraction and magnetization. It crystallizes in B20 cubic structure with lattice parameter ofa= 4.4429 Å. The alloy exhibits two antiferromagnetic transitions AFM-I at 38.44 K and AFM-II at 21.87 K followed by an upturn of magnetization belowTut= 9.79 K as illustrated through the temperature-magnetic fieldT-Hphase diagram. AFM-I state is incommensurate. AFM-II state is weakly correlated as inferred from field-induced transition to AFM-I state. Further, AFM-I state is reported to transform to ferromagnetic state in high magnetic fields. The present study stimulates an approach to derive novel and exotic magnetic materials by substituting rare-earth in transition metal monosilicides.

Spin-disorder intervened avoidance of quantum criticality in B20 cubic Mn1-xVxSi.

The effect of negative chemical pressure with the substitution of transition metal V in an itinerant helimagnetically ordered MnSi, Mn1-xVxSi withx= 0-0.1, is explored using dc and ac-susceptibilities. With increasingx, the manifestations are unaffected crystal structure with increasing unit cell volume, suppression of long-range magnetic order, weakening of itinerant character and reduced spin-cooperative phenomenon. The emergence of spin-glass behaviour forx⩾0.1intervenes in the occurrence of quantum phase transition. The constructed concentration-temperaturex-Tphase diagram illustrates the substitution-driven changes in the magnetism of MnSi. Further, the study suggests that the presence of a precursor state can favour the formation of spin-textures in magnetically ordered compositions0

Structural, magnetic, and dielectric studies on Gd0.7Y0.3MnO3.

Structural, magnetic, specific heat, and dielectric studies were carried out on Y substituted (30 at. %) GdMnO(3) compound as a function of temperature. Anomalies occur at ~41 and 18 K, in the specific heat measurements and are ascribed to paramagnetic, to sinusoidal incommensurate antiferromagnetic transition (ICAFM) and ICAFM to commensurate antiferromagnetic transitions, respectively. Changes in the lattice parameters across these temperatures indicate magneto-elastic coupling present in the compound. However, in the dielectric measurements, an anomaly at 18 K alone is observed and is ascribed to a ferroelectric transition, giving rise to spontaneous ferroelectric ordering at low temperatures. This observation is supported by an anomaly in lattice parameters, across the transition temperature. From the frequency dependent dielectric studies, a strong coupling between Gd(3+) and Mn(3+) magnetic sublattices is inferred and Y substitution results in substantial changes in the relaxation process compared to that of GdMnO(3).