Shape-coupled magnetoresistive structures: a new approach to higher sensitivity

Chen

Physica B: Condensed Matter

2019

The anisotropic magnetoresistance (AMR) in thin permalloy strips was calculated at each steps during magnetization by the finite element method. The magnetization at equilibrium under different external fields was obtained by micromagnetic simulations, while the resistance with different magnetization was obtained by solving the Poisson equations iteratively until self-consistence. We find that the relation between magnetization and AMR deviates from the Stoner-Wohlfarth prediction when the magnetization is reduced from saturation. The reason is that the demagnetization is not necessarily from coherent rotation of the magnetic moment. We conclude that it is necessary to use numeric simulations to optimize the responses of AMR sensors.

Section: Introductionmentioning

confidence: 96%

Probing the relationship between anisotropic magnetoresistance and magnetization of ferromagnetic films

Chen

Physica B: Condensed Matter

2019

“…In particular, it is needed to maximize the AMR effect, which determines the output signal amplitude, and to prevent the strong growth of the coercive force and anisotropy field for maximum sensitivity and minimum hysteresis achievement. However, the magnetoresistive material parameters are determined not only by its internal characteristics, but by the composition and parameters of the film growth, particularly, average grain size [3][4][5][6]. The sensitivity improvement can be achieved, particularly, by alteration of the sensor shape.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Field MEMS-Sensor: Functional Characteristics Control during the Formation of Magnetosensitive Structures

Djuzhev

Iurov

Chinenkov

2018

DDF

In this work the results of substrate temperature effects on coercivity and magnetoresistance in ferromagnetic structures are shown. It was found that with an increase of the substrate temperature from 270 to 390 °C the magnetoresistance increases from 1.2 to 2.3% and the coercive force from 1.6 to 5.3 Oe. A new topology of anisotropic magnetoresistive structures is proposed. In these structures the shape of ferromagnetic elements repeats the shape of nonmagnetic conducting shunts. Sensitivity values obtained for both types of magnetic structures are compared.

J. Sib. Fed. Univ., Math. phys.

“…In this paper we have chosen change in the magnetization distribution in the magnetic strip by changing its geometry. Topology of the magnetic stripe, which is a magnetic layer with a shunt configuration repeating stripes of conductive layer is self-aligned structure [5], was developed as shown in Fig. 3(a).…”

mentioning

confidence: 99%

Technological Features Influence on Magnetic Sensitivity of Sensor Based on Ferromagnetic Structures

Djuzhev¹,

Iurov²,

Chinenkov³

et al. 2017

Main urgent problems of the magnetic devices and primary converters development based on the mag-Creation of magnetic field sensor based on the anisotropic magnetoresistive transducer involves increasing the sensitivity and increase the thermal stability. The sensitivity to the magnetic field, which is determined by the ratio of the signal amplitude imbalance in magnetoresistive bridge caused the by influence of the magnetic field to the value of that field in the linear region of the transfer characteristics of the sensor [1-2] is the most important parameter, because it determines the use of sensors to address various problems. The range of use of magnetoresistive sensors in the technique is extremely wide therefore requirements to sensitivity value are extremely broad. The sensitivity value is influenced by a number of factors, among which first and foremost design and technology. Sensors based on magnetoresistive structures usually consist of a thin strip of magnetic material with thickness 0.03 µm, mainly iron-nickel alloy on which strips of high conductivity material (aluminum) are applied at an angle of 45 o [3]. These sensors are characterized by odd transfer characteristic with a sufficiently large linear range [4]. Studies conducted on various structures have shown that the greatest effect on the sensitivity has width (W) of the magnetic stripe and the distance between shunt strips (a) (Fig. 1, Tab.