  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.
