The Suppression and Recovery of the Ferroelectric Phase in Multiferroic $MnWO_4$ (2008)
Chaudhury, R. P., Lorenz, B., Wang, Y. Q., Sun, Y. Y., Chu, C. W.
We report the discovery of a complete suppression of ferroelectricity in $MnWO_4$ by 10 % iron substitution and its restoration in external magnetic fields. The spontaneous polarization in...
Aiguo, M., Schouten, E.G., Zhang, F.Z., Kok, F.J., Yang, F., Jiang, D.C., ...
In rural China, many pregnant women in their third trimester suffer from anemia (48%) and iron deficiency (ID; 42%), often with coexisting deficiencies of retinol and riboflavin. We investigated the...
Magnetic phase diagrams of the Kagome staircase compound Co3V2O8 (2007)
Yen, F., Chaudhury, R. P., Galstyan, E., Lorenz, B., Wang, Y. Q., Sun, Y. Y., ...
At zero magnetic field, a series of five phase transitions occur in Co3V2O8. The Neel temperature, TN=11.4 K, is followed by four additional phase changes at T1=8.9 K, T2=7.0 K, T3=6.9 K, and T4=6.2...
Incommensurate magnetic structure in the orthorhombic perovskite ErMnO_3 (2007)
Ye, F., Lorenz, B., Huang, Q., Wang, Y. Q., Sun, Y. Y., Chu, C. W., ...
By combining dielectric, specific heat, and magnetization measurements and high-resolution neutron powder diffraction, we have investigated the thermodynamic and magnetic/structural properties of the...
Cruz, C. R. Dela, Lorenz, B., Sun, Y. Y., Wang, Y., Park, S., Cheong, S-W., ...
Measurements of ferroelectric polarization and dielectric constant were done on $R$Mn$_2$O$_5$ ($R$=Tb, Dy, and Ho) with applied hydrostatic pressures of up to 18 kbar. At ambient pressure,...
Thermal expansion and pressure effect in MnWO4 (2007)
Chaudhury, R. P., Yen, F., Cruz, C. R. Dela, Lorenz, B., Wang, Y. Q., Sun, Y. Y., ...
MnWO4 has attracted attention because of its ferroelectric property induced by frustrated helical spin order. Strong spin-lattice interaction is necessary to explain ferroelectricity associated with...
Magnetic Phase Diagrams of Multiferroic Hexagonal RMnO3 (R=Er, Yb, Tm, and Ho) (2007)
Yen, F., Cruz, C. Dela, Lorenz, B., Galstyan, E., Sun, Y. Y., Gospodinov, M., ...
The magnetic phase diagrams of RMnO3 (R = Er, Yb, Tm, Ho) are investigated up to 14 Tesla via magnetic and dielectric measurements. The stability range of the AFM order below the Neel temperature of...
Pressure-Temperature Phase Diagram of Multiferroic $Ni_3V_2O_8$ (2007)
Chaudhury, R. P., Yen, F., Cruz, C. R. Dela, Lorenz, B., Wang, Y. Q., Sun, Y. Y., ...
The pressure-temperature phase diagram of multiferroic $Ni_3V_2O_8$ is investigated for hydrostatic pressures up to 2 GPa. The stability range of the ferroelectric phase associated with the...
Magnetoelastic Effects and Magnetic Phase Diagram of Multiferroic $DyMn_2O_5$ (2006)
Cruz, C. R. Dela, Lorenz, B., Sun, Y. Y., Chu, C. W., Park, S.
The magnetoelastic coupling in multiferroic $DyMn_2O_5$ is investigated by magnetostriction measurements along the three crystallographic orientations. Strong lattice anomalies as a function of the...
Yen, F., Lorenz, B., Sun, Y. Y., Chu, C. W., Bezmaternykh, L. N., Vasiliev, A. N.
GdFe3(BO3)4 exhibits a structural phase transition at 156 K, antiferromagnetic order of the Fe3+ moments at 36 K followed by a spin reorientation phase transition at 9 K. The reorientation phase...
Lorenz, B., Cruz, C. R. Dela, Yen, F., Wang, Y. Q., Sun, Y. Y., Chu, C. W.
Multiferroic rare earth manganites attracted recent attention because of the coexistence of different types of magnetic and ferroelectric orders resulting in complex phase diagrams and a wealth of...
Low temperature dielectric anomalies in HoMnO_3: The complex phase diagram (2005)
Yen, F., Cruz, C. R. Dela, Lorenz, B., Sun, Y. Y., Wang, Y. Q., Gospodinov, M. M., ...
The dielectric constant of multiferroic hexagonal HoMnO_3 exhibits an unprecedented diversity of anomalies at low temperatures (1.8 K< T
Cruz, C. Dela, Yen, F., Lorenz, B., Wang, Y. Q., Sun, Y. Y., Gospodinov, M. M., ...
Evidence for a strong spin-lattice coupling in multiferroic HoMnO_3 is derived from thermal expansion measurements along a- and c-axis. The magnetoelastic effect results in sizable anomalies of the...
Comparative Raman Studies of Sr2RuO4, Sr3Ru2O7 and Sr4Ru3O10 (2004)
Iliev, M. N., Popov, V. N., Litvinchuk, A. P., Abrashev, M. V., Backstrom, J., Sun, Y. Y., ...
The polarized Raman spectra of layered ruthenates of the Srn+1RunO3n+1 (n=1,2,3) Ruddlesden-Popper series were measured between 10 and 300 K. The phonon spectra of Sr3Ru2O7 and Sr4Ru3O10 confirmed...
Large Magneto-Dielectric Effects in Orthorhombic HoMnO3 and YMnO3 (2004)
Lorenz, B., Wang, Y. Q., Sun, Y. Y., Chu, C. W.
We have found a remarkable increase (up to 60 %) of the dielectric constant with the onset of magnetic order at 42 K in the metastable orthorhombic structures of YMnO3 and HoMnO3 that proves the...
Iliev, M. N., Lorenz, B., Litvinchuk, A. P., Sun, Y. Y., Chu, C. W.
Orthorhombic Y$_{1-x}$Ca$_x$MnO$_3$ ($0 \leq x \leq 0.5$) was prepared under high pressure and the variations with $x$ of its structural, magnetic, electrical properties and the polarized Raman...
Field-Induced Resistive Switching in Metal-Oxide Interfaces (2004)
Tsui, S., Baikalov, A., Cmaidalka, J., Sun, Y. Y., Wang, Y. Q., Xue, Y. Y., ...
We investigate the polarity-dependent field-induced resistive switching phenomenon driven by electric pulses in perovskite oxides. Our data show that the switching is a common occurrence restricted...
Raman Phonons and Ageing-Related Surface Disorder in NaxCoO2 (2003)
Iliev, M. N., Litvinchuk, A. P., Meng, R. L., Sun, Y. Y., Cmaidalka, J., Chu, C. W.
The polarized Raman spectra from ab and ac surfaces of single crystal NaxCoO2 (x~0.7), parent compound of recently discovered superconductor NaxCoO2.yH2O, are reported and discussed. The crystals...
Field-Driven Hysteretic and Reversible Resistive Switch at the Ag-Pr0.7Ca0.3MnO3 Interface (2002)
Baikalov, A., Wang, Y. Q., Shen, B., Lorenz, B., Tsui, S., Sun, Y. Y., ...
The hysteretic and reversible polarity-dependent resistive switch driven by electric pulses is studied in both Ag/Pr0.7Ca0.3MnO3/YBa2Cu3O7 sandwiches and single-layer Pr0.7Ca0.3MnO3 strips. The data...
Superconductivity in the C32 Intermetallic Compounds AAl(2-x)Si(x), with A=Ca and Sr, and 0.6 (2002)
Lorenz, B., Lenzi, J., Cmaidalka, J., Meng, R. L., Sun, Y. Y., Xue, Y. Y., ...
The intermetallic compounds AAl2-xSix, where A = Ca, Sr or Ba, crystallize in the C32 structure, same as the recently discovered MgB2 with a high superconducting transition temperature of 39 K. For x...
Nonstoichiometry, Defects and Transport Properties in MgB2 (2001)
Xue, Y. Y., Meng, R. L., Lorenz, B., Meen, J. K., Sun, Y. Y., Chu, C. W.
The local composition Mg:B of MgB2 powder was systematically changed through annealing. Correlations were observed between the Mg loss and the lattice parameters a/c and the microstrain of MgB2....