Magnetic Trampoline Resonators from (La,Sr)MnO3 Single-Crystal Thin Films

TL;DR

This paper introduces magnetic trampoline resonators made from (La,Sr)MnO3 thin films, combining structural and magnetic functionalities, achieving high quality factors and magnetic properties suitable for sensitive magnetic field sensing.

Contribution

The work demonstrates a single-step fabrication of magnetic trampoline resonators from LSMO thin films with high quality factors and intrinsic magnetic properties, simplifying integration for magnetic sensing applications.

Findings

Quality factor up to 60,000 achieved

Magnetic saturation at 240 kA/m at room temperature

Resonators exhibit large magnetic interaction volume

Abstract

Micro-electro-mechanical resonators employing a magnetic element have been proposed for magnetic field sensing applications, but the integration of magnetic materials with standard semiconductor compounds is challenging and requires complex fabrication protocols. We present a different approach relying on (La0.7,Sr0.3)MnO3 (LSMO), an oxide compound that works both as structural element for the resonator and functional magnetic layer. Suspended trampolines are realized in a single step process from LSMO thin films and show quality factor up to 60k and fQ products reaching 10$^{10}$ Hz. Their magnetic properties are probed by a SQUID magnetometer and magnetic force microscopy, showing saturation magnetization of 240 kA/m at room temperature and in-plane magnetic domains with coercivity of 2.5 mT. Being entirely made from a magnetic material, these resonators exhibit a larger magnetic interaction volume compared to other solutions, making them ideal candidates as building blocks for high-sensitivity magnetic field sensors.