Fast Bolometric Response of Bulk La_0.7Sr_0.3MnO₃Electroceramic Structures

Abstract

We report on the performance of a microwave electroceramic bolometer of hybrid Laο.7Srο.3ΜnΟ3/Αl2O3 (0.2 χ 2 χ 4 mm3) structnre. The estimated thermal resistance of the bulk ceramic manganite film-single crystal sapphire interface is about 500 K/W at room temperature. This resistance is the main thermal barrier in the heat sink system and has been found to be slightly dependent on temperature. When compared with the high -Τ superconducting bolometers, the Laο7Srο3ΜnΟ3 microwave electroceramic bolometer works in a more wide temperature range, from 77 Κ to 330 K, excluding the narrow temperature interval at the metal-insulator phase transition (T = 230 K). The microwave electroceramic bolometer sensitivity and the time constant at room temperature have been found to be 0.1 V/W and 100 ms, respectively. To improve the bolometer performance the point contact has been fabricated by a break junction technique. The optimization of a microwave electroceramic bolometer design brought to a considerable improvement of basic bolometer characteristics. The microWave sensitivity was about 0.3 V/W and the time constant was less than 100 ns.PACS numbers: 07.57. Κp, 85.60.Gz, 72.15.Gd The recent progress of film technology in the creation of bolometers and microbolometers using the multi-component materials was achieved at the developing of devices on the base of high temperature superconductors (HTSC). The increasing interest in this field is related to the high superconducting phase transition. The film technology of H TSC assumes the relatively simple production of bolometers and allows to vary the frequency, sensitivity, and speed of response in a widerange due to applications of sublayers, heat barriers, and optimization of (991)

Anomalous photovoltaic effect in Las0.8Sr0.2MnO3films grown on SrTiO3(001) substrates by laser molecular beam epitaxy

“…During the past few years there has been active study of the photoresponse of the manganite thin films. Technological interest has centered on bolometers [7,8], while more basic issues have involved quasi-particle generation and carrier relaxation times [9][10][11].…”