Origin of electromagnon excitations in \textit{R}MnO$_3$ (2008)
Aguilar, R. Valdés, Mostovoy, M., Sushkov, A. B., Zhang, C. L., Choi, Y. J., Cheong, S-W., ...
The origin of electromagnon excitations in cycloidal \textit{R}MnO$_3$ is explained in terms of the Heisenberg coupling between spins despite the fact that the static polarization arises from the...
Lee, Seongsu, Choi, Taekjib, Ratcliff II, W., Erwin, R., Cheong, S-W., Kiryukhin, V.
We report polarized neutron scattering and piezoresponse force microscopy studies of millimeter-sized single crystals of multiferroic BiFeO$_3$. The crystals, grown below the Curie temperature,...
Radaelli, P. G., Vecchini, C., Chapon, L. C., Brown, P. J., Park, S., Cheong, S-W.
We have determined the magnetic structure of the low-temperature incommensurate phase of multiferroic YMn2O5 using single-crystal neutron diffraction. By employing corepresentation analysis, we have...
Multiferroicity in the spin-1/2 quantum matter of LiCu2O2 (2008)
Rusydi, A., Mahns, I., Mueller, S., Ruebhausen, M., Park, S., Choi, Y. J., ...
Multiferroicity in LiCu2O2 single crystals is studied using resonant soft x-ray magnetic scattering, hard x-ray diffraction, heat capacity, magnetic susceptibility, and electrical polarization. Two...
Bajpai, A., Klingeler, R., Wizent, N., Nigam, A. K., Cheong, S-W., Buechner, B.
We present low field thermoremanent magnetization (TRM) measurements in granular CrO2 and composites of ferromagnetic (FM) CrO2 and antiferromagnetic (AFM) Cr2O3. TRM in these samples is seen to...
Epitaxial checkerboard arrangement of nanorods in ZnMnGaO4 films studied by x-ray diffraction (2008)
O'Malley, S. M., Bonanno, P. L., Ahn, K. H., Sirenko, A. A., Kazimirov, A., Park, S., ...
The intriguing nano-structural properties of a ZnMnGaO4 film epitaxially grown on MgO (001) substrate have been investigated using synchrotron radiation-based x-ray diffraction. The ZnMnGaO4 film...
Radaelli, P. G., Chapon, L. C., Daoud-Aladine, A., Vecchini, C., Brown, P. J., Chatterji, T., ...
We employ neutron spherical polarimetry to determine the nature and population of the coexisting antiferromagnetic domains in multiferroic YMn2O5. By applying an electric field, we prove that...
The commensurate phase of multiferroic HoMn2O5 studied by X-ray magnetic scattering (2008)
Beutier, G., Bombardi, A., Vecchini, C., Radaelli, P. G., Park, S., Cheong, S-W., ...
The commensurate phase of multiferroic HoMn2O5 was studied by X-ray magnetic scattering, both off resonance and in resonant conditions at the Ho-L3 edge. Below 40 K, magnetic ordering at the Ho sites...
Complex Spin Structures and Origin of the Magneto-Electric Coupling in YMn2O5 (2008)
Park, S. I., Kenzelmann, M., Schefer, J., ...
By combining neutron four-circle diffraction and polarized neutron diffraction techniques we have determined the complex spin structures of a multiferroic, YMn2O5, that exhibits two ferroelectric...
Kim, M., Barath, H., Cooper, S. L., Abbamonte, P., Fradkin, E., R{ü}bhausen, M., ...
We present Raman scattering studies of the structural and magnetic phases that accompany temperature- and field-dependent melting of charge- and orbital-order (COO) in La0.5Ca0.5MnO3 and...
The commensurate phase of multiferroic HoMn2O5 studied by X-ray magnetic scattering (2008)
Beutier, G, Bombardi, A, Vecchini, C, Radaelli, PG, Park, S, Cheong, S-W, ...
Vecchini, C, Chapon, LC, Brown, PJ, Chatterji, T, Park, S, Cheong, S-W, ...
Spin phonon coupling in frustrated magnet CdCr$_2$O$_4$ (2007)
Aguilar, R. Valdés, Sushkov, A. B., Choi, Y. J., Cheong, S-W., Drew, H. D.
The infrared phonon spectrum of the spinel CdCr2O4 is measured as a function temperature from 6 K to 300K. The triply degenerate Cr phonons soften in the paramagnetic phase as temperature is lowered...
Ratcliff II, W., Huang, Q., Kim, T. H., Cheong, S-W.
ZnCr2O4 undergoes a first order spin-Peierls-like phase transition at 12.5 K from a cubic spin liquid phase to a tetragonal Neel state. Using powder diffraction and single crystal polarized neutron...
Direct observation of oxygen superstructures in manganites (2007)
Grenier, S., Thomas, K. J., Hill, J. P., Staub, U., Bodenthin, Y., García-Fernández, M., ...
We report the observation of superstructures associated with the oxygen 2p-states in two prototypical manganites using x-ray diffraction at the oxygen K-edge. We determine the nature of the orderings...
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,...
Sirenko, A. A., Malley, S. M. O, Ahn, K. H., Park, S., Carr, G. L., Cheong, S-W.
Linearly polarized spectra of far-infrared (IR) transmission in HoMn2O5 multiferroic single crystals have been studied in the frequency range between 8.5 and 105 cm-1 and for temperatures between 5 K...
Symmetry of Multiferroicity in a Frustrated Magnet TbMn$_2$O$_5$ (2007)
Okamoto, J., Huang, D. J., Chao, K. S., Park, S., ...
Based on measurements of soft x-ray magnetic scattering and symmetry considerations, we demonstrate that the magnetoelectric effect in TbMn$_2$O$_5$ arises from an internal field determined by...
Croft, M., Kiryukhin, V., Horibe, Y., Cheong, S-W.
Recent state-of-the-art crystallographic investigations of transition metal spinel compounds have revealed that the d- orbital charge carriers undergo ordering transitions with the formation of local...
Electromagnons in multiferroic YMn2O5 and TbMn2O5 (2006)
Sushkov, A. B., Aguilar, R. Valdes, Park, S., Cheong, S-W., Drew, H. D.
Based on temperature dependent far infrared transmission spectra of YMn2O5 and TbMn2O5 single crystals, we report the observation of electric dipole-active magnetic excitations, or electromagnons, in...
IR Phonon signatures of multiferroicity in TbMn$_{2}$O$_{5}$ (2006)
Aguilar, R. Valdés, Sushkov, A. B., Park, S., Cheong, S-W., Drew, H. D.
The infrared (IR) active phonons in multiferroic TbMn$_2$O$_5$ are studied as a function of temperature. Most of the symmetry allowed IR modes polarized along the \textit{a} and \textit{b} crystal...
Garbarino, G., Acha, C., Levy, P., Koo, T. Y., Cheong, S-W.
We report on DC and pulsed electric field sensitivity of the resistance of mixed valent Mn oxide based La(5/8-y)Pr(y)Ca(3/8)MnO(3) (y = 0.4) single crystals as a function of temperature. The low...
Cruz, C. R. Dela, Yen, F., Lorenz, B., Gospodinov, M. M., Chu, C. W., Ratcliff, W., ...
Strong anomalies of the thermal expansion coefficients at the magnetic and ferroelectric transitions have been detected in multiferroic $RMn_2O_5$. Their correlation with anomalies of the specific...
Kumar, Kranti, Pramanik, A. K., Banerjee, A., Chaddah, P., Roy, S. B., Park, S., ...
Coexisting ferromagnetic and antiferromagnetic phases over a range of temperature as well as magnetic field have been reported in many materials of current interest, showing disorder-broadened 1st...
Shukla, A., Calandra, M., Taguchi, M., Kotani, A., Vanko, G., Cheong, S-W.
X-ray absorption is the standard method to probe the unoccupied density of states at a given edge. Here we show that polarized Resonant Inelastic X-Ray Scattering in La2CuO4 at the Cu K-edge is...
Radaelli, PG, Chapon, LC, Gutmann, MJ, Bombardi, A, Blake, GR, Schmidt, M, ...
Geometrical frustration arises when geometrical constraints promote a locally degenerate ground state. A periodic system with this local geometry may freeze on cooling forming ices or remain...
Ferroelectricity induced by acentric spin-density waves in YMn$_2$O$_5$ (2005)
Chapon, L. C., Radaelli, P. G., Blake, G. R., Park, S., Cheong, S-W.
The commensurate and incommensurate magnetic structures of the magnetoelectric system YMn$_{2}$O$_{5}$, as determined from neutron diffraction, were found to be spin-density waves lacking a global...
Weak ferromagnetic spin and charge stripe order in La[sub 5/3]Sr[sub 1/3]NiO[sub 4] (2005)
Klingeler, R., Buchner, B., Cheong, S-W., Hucker, M.
We present magnetization and specific heat data of a La5/3Sr1/3NiO4 single crystal in high magnetic fields. From the charge and spin stripe ordering temperatures, as well as a magnetic low...
Shukla, A., Calandra, M., Taguchi, M., Kotani, A., Vanko, G., Cheong, S-W.
X-ray absorption is the standard method to probe the unoccupied density of states at a given edge. Here we show that polarized Resonant Inelastic X-Ray Scattering in La2CuO4 at the Cu K-edge is...
Trokiner, A., Verkhovskii, S., Yakubovskii, A., Kumagai, K., Cheong, S-W., Khomskii, D., ...
We present a $^{209}$Bi and $^{17}$O NMR study of the Mn electron spin correlations developed in the charge ordered state of Bi$_{0.5}$Sr$_{0.5}$MnO$_{3}$ and Bi$_{0.5}$Ca$_{0.5}$MnO$_{3}$. The...
Spin structure and magnetic frustration in multiferroic RMn2O5 (R = Tb, Ho, Dy) (2005)
Blake, G. R., Chapon, L. C., Radaelli, P. G., Park, S., Hur, N., Cheong, S-W., ...
We have studied the crystal and magnetic structures of the magnetoelectric materials RMn2O5 (R = Tb, Ho, Dy) using neutron diffraction as a function of temperature. All three materials display...
Inhomogeneous level splitting in Pr2-xBixRu2O7 (2005)
Van Duijn, J, Kim, K H, Hur, N, Adroja, D, Adams, M A, Huang, Q Z, ...
Spin structure and magnetic frustration in multiferroic RMn2O5 (R=Tb,Ho,Dy) (2005)
Blake, G R, Chapon, L C, Radaelli, P G, Park, S, Hur, N, Cheong, S-W, ...
We have studied the crystal and magnetic structures of the magnetoelectric materials RMn2O5 (R=Tb,Ho,Dy) using neutron diffraction as a function of temperature. All three materials display...
Shukla, A., Calandra, M., Taguchi, M., Kotani, A., Vanko, G., Cheong, S-W.
X-ray absorption is the standard method to probe the unoccupied density of states at a given edge. Here we show that polarized Resonant Inelastic X-Ray Scattering in La2CuO4 at the Cu K-edge is...
Shukla, A., Calandra, M., Taguchi, M., Kotani, A., Vanko, G., Cheong, S-W.
X-ray absorption is the standard method to probe the unoccupied density of states at a given edge. Here we show that polarized Resonant Inelastic X-Ray Scattering in La2CuO4 at the Cu K-edge is...
Kiryukhin, V., Borissov, A., Ahn, J. S., Huang, Q., Lynn, J. W., Cheong, S-W.
Neutron scattering measurements on a magnetoresistive manganite La$_{0.75}$(Ca$_{0.45}$Sr$_{0.55}$)$_{0.25}$MnO$_3$ show that uncorrelated dynamic polaronic lattice distortions are present in both...
Direct observation of electronic domains in manganites by spatially resolved spectroscopy (2004)
Sarma, D. D., Topwal, Dinesh, Manju, U., Krishnakumar, S. R., Bertolo, M., La Rosa, S., ...
We use a spatially resolved, direct spectroscopic probe for electronic structure with an additional sensitivity to chemical compositions to investigate high-quality single crystal samples of...
Grenier, S., Hill, J. P., Kiryukhin, V., Ku, W., Thomas, K. J., ...
We report the observation of temperature dependent electronic excitations in various manganites utilizing resonant inelastic x-ray scattering (RIXS) at the Mn K-edge. Excitations were observed...
Temperature-induced barium de-trapping from a double-well potential in Ba6Ge25 (2004)
Schmidt, M, Radaelli, P G, Gutmann, M J, Billinge, S J L, Hur, N, Cheong, S-W
Structural anomalies and multiferroic behavior in magnetically frustrated TbMn2O5 (2004)
Chapon, L C, Blake, G R, Gutmann, M J, Park, S, Hur, N, Radaelli, P G, ...
We have studied the magnetostructural phase diagram of multiferroic TbMn2O5 as a function of temperature and magnetic field by neutron diffraction. Dielectric and magnetic anomalies are found to be...
First-order nature of the ferromagnetic phase transition in (La-Ca)MnO_3 near optimal doping (2003)
Adams, C. P., Lynn, J. W., Smolyaninova, V. N., Biswas, A., Greene, R. L., Ratcliff II, W., ...
Neutron scattering has been used to study the nature of the ferromagnetic transition in single crystals of La_0.7Ca_0.3MnO_3 and La_0.8Ca_0.2MnO_3, and polycrystalline samples of La_0.67Ca_0.33MnO_3...
Average Lattice Symmetry and Nanoscale Structural Correlations in Magnetoresistive Manganites (2003)
Kiryukhin, V., Koo, T. Y., Ishibashi, H., Hill, J. P., Cheong, S-W.
We report x-ray scattering studies of nanoscale structural correlations in the paramagnetic phases of the perovskite manganites La$_{0.75}$(Ca$_{0.45}$Sr$_{0.55}$)$_{0.25}$MnO$_3$,...
Ishibashi, H., Koo, T. Y., Hor, Y. S., Borissov, A., Horibe, Y., Radaelli, P. G., ...
At low temperatures, spinel CuIr$_2$S$_4$ is a charge-ordered spin-dimerized insulator with triclinic lattice symmetry. We find that x-rays induce a structural transition in which the local triclinic...
Charge Ordering Fluctuation and Optical Pseudogap in La$_{1-x}$Ca$_{x}$MnO$_{3}$ (2002)
Kim, K. H., Lee, S., Noh, T. W., Cheong, S-W.
Optical spectroscopy was used to investigate the optical gap (2$\Delta $) due to charge ordering (CO) and related pseudogap developments with x and temperature (T) in La$_{1-x}$Ca$_{x}$MnO$_{3}$...
Formation of isomorphic Ir3+ and Ir4+ octamers and spin dimerization in the spinel CuIr2S4 (2002)
Radaelli, P G, Horibe, Y, Gutmann, M J, Ishibashi, H, Chen, C H, Ibberson, R M, ...
Kiryukhin, V., Koo, T. Y., Borissov, A., Kim, Y. J., Nelson, C. S., Hill, J. P., ...
We report x-ray scattering studies of nanoscale structural correlations in Nd$_{1-x}$Sr$_x$MnO$_3$ and La$_{1-x}$(Ca,Sr)$_x$MnO$_3$, $x$=0.2--0.5. We find that the correlated regions possess a...
Koo, T. Y., Kiryukhin, V., Sharma, P. A., Hill, J. P., Cheong, S-W.
We report synchrotron x-ray scattering studies of charge/orbitally ordered (COO) nanoclusters in Nd$_{0.7}$Sr$_{0.3}$MnO$_3$. We find that the COO nanoclusters are strongly suppressed in an applied...
Martensitic accommodation strain and the metal-insulator transition in manganites (2001)
Podzorov, V., Kim, B. G., Kiryukhin, V., Gershenson, M. E., Cheong, S-W.
In this paper, we report polarized optical microscopy and electrical transport studies of manganese oxides that reveal that the charge ordering transition in these compounds exhibits typical...
Mesoscopic, Non-equilibrium Fluctuations of Inhomogeneous Electronic States in Manganites (2001)
Podzorov, V., Chen, C. H., Gershenson, M. E., Cheong, S-W.
By using the dark-field real-space imaging technique of transmission electron microscopy (TEM), we have observed slow 200 A-scale fluctuations of charge-ordered (CO) phase in mixed-valent manganites...
Kiryukhin, V., Kim, B. G., Katsufuji, T., Hill, J. P., Cheong, S-W.
We report x-ray scattering studies of short-range structural correlations and diffuse scattering in Nd0.5Sr0.5MnO3. On cooling, this material undergoes a series of transitions, first from a...
Mesoscopic and microscopic phase segregation in manganese perovskites (2001)
Radaelli, P G, Ibberson, R M, Argyriou, D N, Casalta, H, Andersen, K H, Cheong, S-W, ...
Correlated Polarons in Dissimilar Perovskite Manganites (2000)
Nelson, C. S., Zimmermann, M. V., Hill, J. P., Gibbs, Doon, Kiryukhin, V., Koo, T. Y., ...
We report x-ray scattering studies of broad peaks located at a (0.5 0 0)/(0 0.5 0)-type wavevector in the paramagnetic insulating phases of La_{0.7}Ca_{0.3}MnO_{3} and Pr_{0.7}Ca_{0.3}MnO_{3}. We...
Kiryukhin, V., Kim, B. G., Podzorov, V., Cheong, S-W., Koo, T. Y., Hill, J. P., ...
The insulator-metal transition in single crystal La(5/8-y)Pr(y)Ca(3/8)MnO3 with y=0.35 was studied using synchrotron x-ray diffraction, electric resistivity, magnetic susceptibility, and specific...
High Temperature Charge-Ordering Fluctuation in Manganites (2000)
Kim, K. H., Uehara, M., Cheong, S-W.
High temperature (T) studies of La_{1-x}Ca_{x}MnO_{3} show that charge and phonon transport is significantly suppressed in a narrow doping region of x~1/2 and in a wide T range up to 900 K, which...
Smolyaninova, V. N., Biswas, Amlan, Zhang, X., Kim, K. H., Kim, Bog-Gi, Cheong, S-W., ...
We report low temperature specific heat measurements of Pr$_{1-x}$Ca$_{x}$MnO$_{3}$ ($0.3\leq x \leq 0.5$) and La$_{0.5}$Ca$_{0.5}$MnO$_{3}$ with and without applied magnetic field. An excess...
Yoon, S., Rubhausen, M., Cooper, S. L., Kim, K. H., Cheong, S-W.
We report an inelastic light scattering study of the effects of charge-ordering on the spin-, charge-, and lattice-dynamics in ${\rm Bi}_{1-x}{\rm Ca}_{x}{\rm MnO}_3$ $(x>0.5)$. We find that...
Kim, K. H., Uehara, M., Hess, C., Sharma, P. A., Cheong, S-W.
We measured thermal conductivity, k, thermoelectric power, S, and dc electric conductivity, sigma, of La_{5/8-x}Pr_{x}Ca_{3/8}MnO_{3}, showing an intricate interplay between metallic ferromagnetism...
Charge and Spin Order in La2-xSrxNiO4 (x=0.275 and 1/3) (2000)
Cheong, S-W., Yamada, K., Majkrzak, C.
We report polarized and unpolarized neutron diffraction measurements on La2-xSrxNiO4 (x=0.275 and 1/3). The data for the spin ordered states are consistent with a collinear spin model in which spins...
Podzorov, V., Uehara, M., Gershenson, M. E., Cheong, S-W.
We observed a dramatic peak in the 1/f noise at the metal-insulator transition (MIT) in low-Tc manganites. This many-orders-of-magnitude noise enhancement is observed for both polycrystalline and...