Nmagnetoresistance of semiconductor pdf

Semiconductors are good for testing theory because they offer another dimension for measuring resistivity. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. The silicon becomes an ntype semiconductor because of the addition of. Separating positive and negative magnetoresistance in organic semiconductor devices f. Magnetoresistance in semiconductor metal hybrids for power applications presented by clay nunnally, a candidate for the degree of doctor of philosophy and hereby certify that, in their opinion, it is worthy of acceptance. But the garnetmade isolators have not been monolithically integrated with semiconductor optoelectronic devices, because these oxide crystals can not be grown on semiconductor substrates. The phenomenon of transverse magnetoresistance will be observed in an extrinsic semiconductor. In other words, the flow of electric current through the magneto resistor changes when an external magnetic field is applied to it. Ferromagnetism and giant magnetoresistance in zincblende. Earlier researches show that nonmagnetic semiconductormetal hybrid structures exhibit a very large magnetoresistance effect, the socalled extraordinary magnetoresistance effect. Hall coefficient and magnetoresistance of semiconductors. The underlying principle of this phenomenon is a change of the current path in the hybrid structure upon application of a magnetic field, due to the lorentz force.

Very large tunneling magnetoresistance in layered magnetic. Magnetic semiconductors are semiconductor materials that exhibit both ferromagnetism or a similar response and useful semiconductor properties. In the late 1940s the invention of the transistor was the start of a rapid development. Magnetooptical devices for optical integrated circuits. The pace of semiconductor materials and device development has been staggering, and the impact on human society monumental. Anisotropic magnetoresistance in an antiferromagnetic.

If implemented in devices, these materials could provide a new type of control of conduction. The effect of electric field on the semiconductor surface. Semiconductors with electric and magnetic properties. Magnetoresistive angular sensors nxp semiconductors. Mr sensors operate virtually independent of magnet shifts and drifts due to lifetime, thermal influences or mechanical stress. Ravindran, phy02e semiconductor physics, 30 january 20. Describe how current is produced in a semiconductor. Their faraday rotation can be up to six orders of magnitude higher than that of nonmagnetic semiconductors. There are a variety of effects that can be called magnetoresistance. Magnetic force revisited you saw in an earlier section that charges moving through a magnetic field experience a magnetic force given by f b qv x b. The semiconductor materials used in electronic devices are doped under precise conditions to control the concentration and regions of p and ntype dopants.

In this dissertation, the extraordinary magnetoresistance emr effect in semiconductormetal hybrid structures is studied to improve the performance in sensing applications. Magneto resistor is a type of resistor whose resistance changes when an external magnetic field is applied. Semiconductor devices are nowadays commonplace in every household. Using twodimensional finite element simulations, the geometric dependence of the output sensitivity, which is a more relevant parameter for emr sensors than the. This is the influence of impurities in semiconductors. New kind of magnetoresistance has implications for. The magnetoresistance for temperatures below 19 k has been previously reported for this sample where a negative magnetoresistance of 0. Magnetoresistance article about magnetoresistance by the. Nxps magnetoresistive angular sensors, by using a true angular measurement, approach work accurately and reliably with no magnetic field strength variations. While conventional mr effects are rather small in most semiconductors. Magnetoresistance and hall effect in the ferromagnetic semiconductor ga1xmnxas k w edmonds, r p campion, ky wang, a c neumann, b l gallagher, c t foxon, p c main school of physics and astronomy, university of nottingham, nottingham ng7 2rd, uk abstract.

Here, we designed a modified semiconductormetal hybrid device with i v i v i configuration, where i and v represent current lead and voltage probe. Magnetism and semiconducting properties are known to coexist in some ferromagnetic. Figure 110 the energy band diagram of a semiconductor. Matthew melissa physics 141a spring 20 1 giant magnetoresistance matthew melissa april 4, 20. Electrical resistivity and hall effect part i overview. Magnetoresistance in semiconductormetal hybrids for power applications presented by clay nunnally, a candidate for the degree of doctor of philosophy and hereby certify that, in their opinion, it is worthy of acceptance. Paramagnetic semiconductor cd 1x mn x te is promising as a magnetooptical.

Magnetoresistance an overview sciencedirect topics. The spinpolarized carriers are injected and collected by single crystal fe elements, for which the. Dowell associate professor of electrical and computer engineering. Magnetoresistance definition is a change in electrical resistance due to the presence of a magnetic field. Magnetoresistance effects in hybrid semiconductor devices. Specifically, the ratio of current, flowing through the highly conducting metal and. Universal properties of linear magnetoresistance in strongly disordered mnasgaas. Whereas traditional electronics are based on control of charge carriers nor ptype, practical magnetic semiconductors would also allow control of quantum. The magnitude of the effect in materials used in the recording industry has. This vlmr occurs when the electrons occupy the open fermi surface and their motion. Magnetoresistivity can now depend on magnetic field, angle, and.

Marius grundmann the physics of semiconductors fulvio frisone. Plots of magnetoresistance versus magnetic field at four different temperatures are shown in. Gatetunable large magnetoresistance in an allsemiconductor spintransistorlike device m. Separating positive and negative magnetoresistance in. The resistivity, temperature, and magnetic field dependence of the anomalous hall effect in a series of metallic ga1. The resistance of some of the metal and the semiconductor material varies in the presence of the magnetic field, this effect is called the magnetoresistance. In a thought experiment in free space, another observer, attached to frame o x,y,z, moves at velocity v c2. Today, highly integrated semiconductor detector systems with tens of thousands of. Extraordinary magnetoresistance effect in semiconductor.

Hall coefficient and transverse magnetoresistance of narrow. Magnetoresistance effects in hybrid semiconductor devices citation for published version apa. Discuss insulators, conductors, and semiconductors and how they differ. Magnetic properties of gamnas nanodot arrays fabricated using porous alumina templates1pg. In the second part of the experiment you will study a semiconductor germanium crystal where the leads have already been attached. Magnetic field can also be used to cause the metal to semiconductor transition, a phenomenon also called colossal magnetoresistance. Issues in colossal magnetoresistance cmr manganese oxides. Ferromagneticiiiv semiconductor heterostructures and. The element which has these effects is known as the magnetoresistor.

The dependence of the magnetoresistance on applied magnetic field will be determined and compared to theoretical predictions. Giant room temperature magnetoresistance in singlecrystal femgofe magnetic tunnel juctins, nature vol. Basic semiconductor material science and solid state physics. Influence of voltage on magnetization of ferromagnetic. Magnetoresistance of inmnas magnetic semiconductors. It is shown that in a weak magnetic field the transport coefficients exhibit non. The x is a crossproduct, which means that the magnitude size of the force is found from. The fifth electron becomes a conduction electron that is donated to the conduction band. Magnetoresistance measurements also yield information about current carrier mobilities. Coey physics department, trinity college, dublin 2 ireland.

Novel experimental setup to study the magnetoresistance. To observe the phenomenon of magnetoresistance in a semic onductor and study the magnetic eld dependence of the transverse magnetoresistance of a given semiconductor sample. You will 1 measure the temperaturedependence of resistivity, 2 determine the energy gap e g, and 3 study the hall effect. Magnetoresistance is the tendency of a material often ferromagnetic to change the value of its electrical resistance in an externallyapplied magnetic field. Germanium is a typical electronic semiconductor with a cubic lattice. Magnetic semiconductors strong magnetooptical effect allows the material to be used in optical modulators. Magnetoelectronics at edges in semiconductor structures. In other words, the magnetoresistor is a type of resistor whose resistance varies with the magnetic field. Four probe arrangement, sample, magnetoresistance setup. Magnetoresistance overview janicenickel computerperipheralslaboratory hpl9560 june, 1995 magnetoresistance, sal, dualstripe, spinvalve, gmr magnetoresistance, the change of a materials resistivity with the application of a magnetic field, is a well known phenomenon. Extraordinary magnetoresistance in semiconductormetal. Electronics tutorial on semiconductor basics explaining what ntype and ptype materials are along with conductors, insulators and resistivity.

Vertical longitudinal magnetoresistance vlmr caused by the peculiar shape of the fermi surface of a superlattice has been observed in gaasalxga1xas superlattices. The origin of ferromagnetism kaili zhang literature seminar september 18, 2014 a dilute magnetic semiconductor dms is a semiconductor material that has been made ferromagnetic through doping with transition metal cations at low concentrations. Magnetoresistance and hall effect in the ferromagnetic. Magnetoresistance of semiconductormetal hybrid structures. Dowell associate professor of electrical and computer.

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