Low-noise La0.7Sr0.3MnO3 thermometers for uncooled bolometric applications

Abstract

We report measurements of the temperature coefficient of the resistance (TCR) and the low-frequency noise of epitaxial La0.7Sr0.3MnO3 (LSMO) thin films deposited on SrTiO3 (STO) and (LaAlO3)0.3(Sr2AlTaO6)0.7 substrates. An x-ray-diffraction study showed that the films were (001) oriented. A normalized Hooge parameter of 9×10−31m3 was measured at 300K in the case of a 10-μm-wide, 575-μm-long line patterned in the 200-nm-thick film grown on STO substrate. This value is among the lowest reported values for manganites and close to values measured in standard metals and semiconductors. The corresponding noise equivalent temperature (NET) was constant in the 300–340K range and equal to 6×10−7KHz−1∕2 at 10Hz and 150μA for a 10-μm-wide, 575-μm-long line patterned in a 200-nm-thick LSMO film. This very low NET value is comparable to the best published results for manganites and was even found to be lower than the NET of other uncooled thermometers such as amorphous semiconductors, vanadium oxides, or semiconducting YBa2Cu3O6+σ. This can easily be explained by the lower noise level of epitaxial manganites thin films compared to others. The results show that despite a TCR of only 0.017K−1 at 300K, and thanks to a very low-noise level, LSMO thin films are real potential material for uncooled thermometry and bolometry.

Magnetocaloric effect and temperature coefficient of resistance of La0.85Ag0.15MnO3epitaxial thin films obtained by polymer-assisted deposition

“…5b) respectively. These values are slightly higher than those reported in manganite thin films being considered for bolometric applications, in which the TCR coefficient in the 1-3 % K -1 range [9].…”

Low-field microwave absorption in epitaxial La0.7Sr0.3MnO3films

“…We studied La 0.7 Sr 0.3 MnO 3 films with thicknesses d =50, 100, 150, and 200 nm. The films were grown by the pulsed laser deposition technique on the ∼ 5 × 5 × 1 mm 3 (001) SrTiO 3 substrates in two different laboratories [39,40] and have T C of 330 K. The FMR measurements in the parallel field showed biaxial (four-fold) in-plane anisotropy of all these epitaxial films. We measured magnetically-modulated microwave absorption and dispersion in 1 × 1 mm 2 pieces of these films when the magnetic field was swept from large negative to large positive values (typically, from -10 kOe to 10 kOe).…”

Nb5N6 thin film on silicon and silicon oxide: A good material for terahertz detection

“…Under a gas mixture condition of N 2 :Ar = 4:1, the TCRs of the Nb 5 N 6 thin films are 0.65% K 1 for SiO 2 /Si(100) substrate and 0.91% K 1 for SiO 2 substrate at room temperature, they are much higher than those grown on Si (100) substrates. Those TCRs also outclass platinum (0.25% K 1 ) [3] , Nb ( 0.1% K 1 ) [2] , single-walled carbon nanotubes (SWCNTs, 0.17% K 1 ) [7] , permalloy on Si(100) (0.25% K 1 ) [8] and can be comparable to La 0.7 Sr 0.3 MnO 3 (LSMO) (1.7% K 1 ) [9] . In conclusion, by optimizing the deposition parameters, we have successfully fabricated Nb 5 N 6 thin film with larger TCR on Si(100), SiO 2 /Si(100), crystal SiO 2 substrates by using r f magnetron sputtering.…”