C. R. dela Cruz

Magnetic order of the iron spins in NdFeAsO

Polarized and unpolarized neutron-diffraction measurements have been carried out to investigate the iron magnetic order in undoped NdFeAsO. Antiferromagnetic order is observed below [4](6) K, which is in close proximity to the structural distortion observed in this material. The magnetic structure consists of chains of parallel spins that are arranged antiparallel between chains, which is the same in-plane spin arrangement as observed in all the other iron oxypnictide materials. Nearest-neighbor spins along the c axis are antiparallel like LaFeAsO. The ordered moment is 0.25(7) mu(B), which is the smallest moment found so far in these systems.

Structural anomalies at the magnetic and ferroelectric transitions in RMn 2 O 5 (R=Tb,Dy,Ho)

Strong anomalies of the thermal expansion coefficients at the magnetic and ferroelectric transitions have been detected in multiferroic

Pressure-induced enhancement of ferroelectricity in multiferroic R Mn 2 O 5 ( R = Tb , Dy , Ho )

RMn_2O_5

Low-temperature dielectric anomalies in HoMn O3 : The complex phase diagram

. Their correlation with anomalies of the specific heat and the dielectric constant is discussed. The results provide evidence for the magnetic origin of the ferroelectricity mediated by strong spin-lattice coupling in the compounds. Neutron scattering data for

Pressure-temperature phase diagram of multiferroic Ni 3 V 2 O 8

HoMn_2O_5

Evidence for strong spin-lattice coupling in multiferroic RMn2O5(R=Tb,Dy,Ho) via thermal expansion anomalies

indicate a spin reorientation at the two low-temperature phase transitions.

Ba 8 CoNb 6 O 24 : A spin- 1 2 triangular-lattice Heisenberg antiferromagnet in the two-dimensional limit

Measurements of ferroelectric polarization and dielectric constant were done on

Coexistence of ferromagnetism and superconductivity in CeO 0.3 F 0.7 BiS 2

R

Up-up-down-down magnetic chain structure of the spin- 12 tetragonally distorted spinel GeCu2O4

Mn

Unusual UUDD magnetic chain structure of the spin-1/2 tetragonally distorted spinel GeCu2O4

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