Design and analysis of magnetostrictive sensors for wireless temperature sensing

Abstract

Magnetostrictive transducers are commonly used as actuators, sonar transducers, and in remote non-destructive evaluation. Their use in wireless thermometry is relatively unexplored.Since magnetostriction-based sensors are passive, they could potentially enable long-term nearfield thermometry. While the temperature sensitivity of resonance frequency in magnetostrictive transducers has been reported in previous studies, the origin of the temperature sensitivity has however not been elucidated. Here, we identify material properties that determine temperature sensitivity, and identify ways to improve sensitivity as well as the detection technique. Using a combination of analytical and computational methods, we systematically identify the material properties that directly influence the temperature coefficient of resonance frequency (TCF). We first experimentally measure the shift in resonance frequency due to temperature changes in a Metglas strip to be 0.03%K -1 . Using insights from theory, we then experimentally demonstrate a 5-fold improvement to the TCF by using Terfenol in place of Metglas as the magnetostrictive sensor material. We further demonstrate an alternate temperature sensing technique that does not require measuring the resonance frequency, consequently reducing instrument complexity. This work provides a general framework to analyze magnetostrictive materials and the sensing scheme for near-field wireless thermometry.

Recent Advances in Magnetostrictive Tb-Dy-Fe Alloys

“…To explore its application, some researchers sputtered Tb-Dy-Fe film on a Fe-Co substrate, and the composite film was expected to be used in high-precision nondestructive testing [100]. In recent years, an application in wireless temperature measurement was developed, in which Terfenol-D was used to increase the temperature coefficient of resonant frequency [101].…”