T8480 输出模块

T8480 输出模块

【产品详情】

TMR 效应就是一种关于自旋极化运输过程的现象。TMR 效应的产生机理是自旋相关的隧穿效应，TMR的结构为铁磁层/非磁绝缘层/铁磁层(FM//FM)的三明治结构。饱和磁化时，两铁磁层的磁化方向互相平行，而通常两铁磁层的矫顽力不同。因此反向磁化时,矫顽力小的铁磁层磁化矢量首先翻转，使得两铁磁层的磁化方向变成反平行。
电子从一个磁性层隧穿到另一个磁性层的隧穿几率与两磁性层的磁化方向有关。若两层磁化方向互相平行，则在一个磁性层中多数自旋子带的电子将进入另一磁性层中多数自旋子带的空态，少数自旋子带的电子也将进入另一磁性层中少数自旋子带的空态，总的隧穿电流较大，若两磁性层的磁化方向反平行，情况则刚好相反，即在一个磁性层中，多数自旋子带的电子将进入另磁性层中少数自旋子带的空态，而少数自旋子带的电子也将进入另一磁性层中多数自旋子带的空态，这种状态的隧穿电流比较小。因此，隧穿电导随着两铁磁层磁化方向的改变而变化，碰化矢量平行时的电导高于反平行时的电导。通过施加外磁场可以改变两铁磁层的磁化方向，从而使得隧穿电阻发生变化，导致 TMR 效应的出现。
当磁体在TMR传感器上旋转时，自由层的磁化方向跟随磁体的磁场方向，元件的电阻不断变化。由于电阻值与钉扎层和自由层的磁化方向之间的相对角度成正比，因此TMR元件可以用作角度传感器
因为TMR传感器的电阳值与钉扎层和自由层的磁化方向之间的相对角度成正比，所以它可以进行360%角度检测。另外TMR传感器的输出是霍尔元件的 500 倍，而且功耗低(推荐条件下为 5mw)，非常适合用作汽车应用的传感器。例如，它们可以替代使用霍尔元件的传统角度传感器，如汽车转向角度传感器或 EPS(电动助力转向)电机角度传感器。同时TMR传感器的低温漂性非常适合汽车以及各类工业设备。

T8480

The TMR effect is a phenomenon related to spin polarization transport process. The mechanism of TMR effect is spin-dependent tunneling effect, and the structure of TMR is a sandwich structure of ferromagnetic layer/non-magnetic insulation layer/ferromagnetic layer (FM//FM). In saturation magnetization, the magnetization direction of the two ferromagnetic layers is parallel to each other, and usually the coercivity of the two ferromagnetic layers is different. Therefore, when the magnetization is reversed, the magnetization vector of the ferromagnetic layer with low coercivity is flipped first, so that the magnetization direction of the two ferromagnetic layers becomes anti-parallel.
The tunneling probability of electrons from one magnetic layer to another is related to the direction of magnetization of the two magnetic layers. If the magnetization direction of the two layers is parallel to each other, most of the electrons of the spin belt in one magnetic layer will enter the empty state of the majority of the spin belt in the other magnetic layer, and a few of the electrons of the spin belt will also enter the empty state of the few spin belt in the other magnetic layer, the total tunneling current is larger, if the magnetization direction of the two magnetic layers is anti-parallel, the situation is just the opposite, that is, in a magnetic layer, Most of the electrons in the spin belt will enter the empty state of the few spin belts in the other magnetic layer, and the few electrons in the spin belt will also enter the empty state of the most spin belts in the other magnetic layer, which has a relatively small tunneling current. Therefore, the tunneling conductance changes with the direction of magnetization of the two ferrospheres, and the conductance when the collision vector is parallel is higher than that when it is antiparallel. By applying an external magnetic field, the direction of magnetization of the two ferromagnetic layers can be changed, which changes the tunneling resistance and leads to the appearance of TMR effect.
When the magnet rotates on the TMR sensor, the magnetization direction of the free layer follows the magnetic field direction of the magnet, and the resistance of the element constantly changes. Since the resistance value is proportional to the relative Angle between the direction of magnetization of the pinned layer and the free layer, the TMR element can be used as an Angle sensor
Because the electropositive value of the TMR sensor is proportional to the relative Angle between the direction of magnetization of the pinned layer and the free layer, it can perform 360% Angle detection. In addition, the output of the TMR sensor is 500 times that of the Hall component, and the power consumption is low (5mw under recommended conditions), making it ideal for use as a sensor for automotive applications. For example, they can replace traditional Angle sensors that use Hall components, such as automotive steering Angle sensors or EPS(electric Power steering) motor Angle sensors. At the same time, the low temperature bleachability of TMR sensors is very suitable for automobiles and various industrial equipment.

T8480