This paper describes a wireless, remote query glucose biosensor using a ribbonlike, mass-sensitive magnetoelastic sensor as the transducer. The glucose biosensor is fabricated by first coating the magnetoelastic sensor with a pH-sensitive polymer and upon it a layer of glucose oxidase (GOx). The pH-responsive polymer swells or shrinks, thereby changing mass, respectively, in response to increas...

The determination of body fluid acidity using a wireless magnetoelastic pH-sensitive sensor is described. The sensor was fabricated by casting a layer of pH-sensitive polymer on a magnetoelastic ribbon. In response to an externally applied time-varying magnetic field, the magnetoelastic sensor mechanically vibrates at a characteristic frequency that is inversely dependent upon the mass of the p...

A GaMnAs nanoelectromechanical resonator is used to obtain the first measurement of magnetostriction in a dilute magnetic semiconductor. Resonance frequency shifts induced by field-dependent magnetoelastic stress are used to simultaneously map the magnetostriction and magnetic anisotropy constants over a wide range of temperatures. Owing to the central role of carriers in controlling ferromagne...

Influence of the magnetoelastic interaction on the structural phase transitions in cubic ferromagnets is investigated on the basis of a Ginzburg-Landau theory. It is shown that for the case of a positive magnetic anisotropy constant the structural phase transitions are not accompanied by a spin-reorientation. In the magnetic state the high-temperature phase has small deformations caused by the ...

Magnetoelastic sensors as an important type of acoustic wave sensors have shown great promise for a variety of applications. Mass sensitivity is a key parameter to characterize its performance. In this work, the effects of mass load distribution on the mass sensitivity of a magnetoelastic sensor under different resonance modes were theoretically investigated using the modal analysis method. The...

Room-temperature perpendicular magnetic anisotropy ~PMA! was observed in Ni/Pt multilayer films having 7–30 Å Ni and constant 3 Å Pt sublayer thickness, prepared by magnetron sputtering at an Ar sputtering pressure of 7 mTorr. To understand the origin of PMA, the magnetoelastic anisotropy was determined from delicate in situ stress and ex situ magnetostriction coefficient measurements. Tensile ...

Magnons and phonons are fundamental quasiparticles in a solid and can be coupled together to form a hybrid quasi-particle. However, detailed experimental studies on the underlying Hamiltonian of this particle are rare for actual materials. Moreover, the anharmonicity of such magnetoelastic excitations remains largely unexplored, although it is essential for a proper understanding of their diver...

The main advantage of magnetoelastic sensors in comparison with the classic wire ones or semiconductor ones is their marked sensitivity and higher resistance to environmental moisture. These properties predestinate them for use in civil engineering and geo-technological applications [2]. Magnetoelastic sensors of pressure force are currently based on the change of core permeability caused by me...

In response to a magnetic field impulse, magnetostrictive magnetoelastic sensors mechanically vibrate. These vibrations can be detected in several ways: optically from the amplitude modulation of a reflected laser beam, acoustically using a microphone or hydrophone, and by using a pickup coil to detect the magnetic flux emitted from the sensor. Earlier work has shown that the resonant frequency...

The main parameters of magnetoelastic resonators in the detection of chemical (i.e., salts, gases, etc.) or biological (i.e., bacteria, phages, etc.) agents are the sensitivity S (or external agent change magnitude per Hz change in the resonance frequency) and the quality factor Q of the resonance. We present an extensive study on the experimental determination of the Q factor in such magnetoel...