15 research outputs found
Relaxation of transport properties in electron doped SrTiO3
We electron-dope single crystal samples of SrTiO_3 by exposing them to Ar^+
irradiation and observe carrier mobility similar in its magnitude and
temperature dependence to the carrier mobility in other electron-doped SrTiO3
systems. We find that some transport properties are time-dependent. In
particular, the sheet resistance increases with time at a temperature-dependent
rate, suggesting an activation barrier on the order of 1 eV. We attribute the
relaxation effects to diffusion of oxygen vacancies - a process with energy
barrier similar to the observed activation energy
Interplay between sheet resistance increase and magnetotransport properties in
We find that the sheet resistance () of patterned samples of with a length scale of several microns may increase
significantly at low temperatures in connection with driving electrical
currents and applying in-plane magnetic fields. As the samples are warmed up,
recovers to its original value with accelerated recovery near ${\rm 70 \
K}{\rm 160 \ K}R_s$, the carrier
density and the mobility decrease and magnetotransport properties which may be
linked to magnetism are suppressed.Comment: 6 pages, 6 figure
Uniaxial magnetocrystalline anisotropy in
is a paramagnetic metal and since its low temperature
resistivity is described by with , it
is also considered a non-Fermi liquid (NFL) metal. We have performed extensive
magnetoresistance and Hall effect measurements of untwinned epitaxial films of
. These measurements reveal that exhibits
uniaxial magnetocrystalline anisotropy. In addition, the low-temperature NFL
behavior is most effectively suppressed when a magnetic field is applied along
the easy axis, suggesting that critical spin fluctuations, possibly due to
proximity of a quantum critical phase transition, are related to the NFL
behavior.Comment: 7 figure
Composed planar Hall effect sensors with dual-mode operation
We present a composed planar Hall effect sensor with two modes of operation: (a) an ON mode where the composed sensor responds to magnetic field excitations similarly to the response of a regular planar Hall effect sensor, and (b) an OFF mode where the response is negligible. The composed planar Hall effect sensor switches from the OFF mode to the ON mode when it is exposed to a magnetic field which exceeds a certain threshold determined by the sensor design. The features of this sensor make it useful as a switch triggered by magnetic field and as a sensing device with memory, as its mode of operation indicates exposure to a magnetic field larger than a certain threshold without the need to be activated during the exposure itself