Effect of temperature on magnetoimpedance in amorphous microconducts Co$_{27.4}$Fe$_5$Ni$_{43.08}$B$_{12.26}$Si$_{12.26}$

A study of the temperature behavior of high-frequency magnetoimpedance (MI) in amorphous microcircuits in a glass shell up to the Curie temperature TC has been carried out. Samples from the alloy Co$_{27.4}$Fe$_5$Ni$_{43.08}$B$_{12.26}$Si$_{12.26}$ with a low Curie temperature ($T_{\mathrm{C}}\sim$ 48$^\circ$C) and negative magnetostriction were used. Near $T_{\mathrm{C}}$, the impedance curves retain their characteristic behavior for materials with circular anisotropy, but the sensitivity of MI with respect to the field decreases sharply. The change in impedance with temperature becomes significant only in the presence of an external magnetic field. With an increase in temperature from room temperature to $T_{\mathrm{C}}$, the relative change in impedance can reach 140–275% in the frequency range 0.1–0.9 GHz and a magnetic field of $\sim$10 Oe. Taking into account the location of $T_{\mathrm{C}}$ in an almost important temperature region, the results obtained are interesting for the development of miniature temperature sensors, including contactless embedded sensors.