140 research outputs found
Robust charge and magnetic order under electric field and current in the multiferroic LuFe(2)O(4)
We performed elastic neutron scattering measurements on the charge- and
magnetically-ordered multiferroic material LuFe(2)O(4). An external electric
field along the [001] direction with strength up to 20 kV/cm applied at low
temperature (~100 K) does not affect either the charge or magnetic structure.
At higher temperatures (~360 K), before the transition to three-dimensional
charge-ordered state, the resistivity of the sample is low, and an electric
current was applied instead. A reduction of the charge and magnetic peak
intensities occurs when the sample is cooled under a constant electric current.
However, after calibrating the real sample temperature using its own
resistance-temperature curve, we show that the actual sample temperature is
higher than the thermometer readings, and the "intensity reduction" is entirely
due to internal sample heating by the applied current. Our results suggest that
the charge and magnetic orders in LuFe(2)O(4) are unaffected by the application
of external electric field/current, and previously observed electric
field/current effects can be naturally explained by internal sample heating.Comment: Version as appeared in PRB
Magnetic field induced enhancement of spin-order peak intensity in La(1.875)Ba(0.125)CuO(4)
We report on neutron-scattering results on the impact of a magnetic field on
stripe order in the cuprate LaBaCuO. It is found that a
7 T magnetic field applied along the {\it c} axis causes a small but finite
enhancement of the spin-order peak intensity and has no observable effect on
the peak width. Inelastic neutron-scattering measurements indicate that the
low-energy magnetic excitations are not affected by the field, within
experimental error. In particular, the small energy gap that was recently
reported is still present at low temperature in the applied field. In addition,
we find that the spin-correlation length along the antiferromagnetic stripes is
greater than that perpendicular to them.Comment: 4 pages, 5 figure
- …