Novel excitations near quantum criticality in geometrically frustrated antiferromagnet CsFeCl.

The investigation of materials that exhibit quantum phase transition provides valuable insights into fundamental problems in physics. We present neutron scattering under pressure in a triangular-lattice antiferromagnet that has a quantum disorder in the low-pressure phase and a noncollinear structure in the high-pressure phase. The neutron spectrum continuously evolves through critical pressure; a single mode in the disordered state becomes soft with the pressure and it splits into gapless and gapped modes in the ordered phase.

Neutron Spin Resonance in the 112-Type Iron-Based Superconductor.

We use inelastic neutron scattering to study the low-energy spin excitations of the 112-type iron pnictide Ca_{0.82}La_{0.18}Fe_{0.

Magnetic ordering in relation to the room-temperature magnetoelectric effect of Sr3Co2Fe24O41.

The origin of a room-temperature magnetoelectric (ME) effect has been examined by means of neutron powder diffraction measurements for a Z-type hexaferrite Sr(3)Co(2)Fe(24)O(41). The temperature and magnetic-field dependence of the electric polarization P and several magnetic Bragg reflections show that a commensurate magnetic order with a (0,0,1) propagation vector has an intimate connection with the ME effect. The room-temperature ME effect can be understood in terms of the appearance of P which is induced by a transverse conical spin structure through the inverse Dzyaloshinskii-Moriya mechanism in analogy with Y-type hexaferrites.