Motivated by recent experiments, we theoretically study the domainwall dw magnetoresistance dwmr in antiferromagnetic afm metals. Princeton university library one washington road princeton, nj 085442098 usa 609 2581470. Measuring the electrical resistance of a material in a magnetic field the magnetoresistance is often a first step on the road to discovering new electronic properties. Angular dependence of magnetoresistance and fermisurface. From early measurements on noble metals to definitive characterization of localization effects in semiconductors to recent studies of topological materials, the magnetoresistive response provides an experimental technique to explore the fermi surface in detail, and to predict and craft physical. The magnetoresistance effect is proportional to the magnetic field change at larger magnetic flux densities, as shown in figure 31. A large negative magnetoresistance nmr is anticipated in topological semimetals in parallel magnetic fields, demonstrating the chiral anomaly, a longsought highenergyphysics effect, in solid. Brief description of the anisotropic magnetoresistance effect the discovery of anisotropic magnetoresistance in ferro magnetic metals was made by william thomson 1 j in glascow in 1857. The peculiar band structure of semimetals exhibiting dirac and weyl crossings can lead to spectacular electronic properties such as large mobilities accompanied by extremely high magnetoresistance. The large magnetoresistance effect of sndoped insb singlecrystal thin film is now used practically. In the free atoms, the 3d and 4s levels of the 3d transition elements are hosts for the valence electrons. Materials free fulltext magnetoresistance and thermal. First published in 1989, this book contained the first systematic account of magnetoresistance in metals, the study of which has provided solidstate physicists with much valuable information about the level of treatment is aimed at readers with a basic knowledge of undergraduate solidstate physics, and makes no great demand on mathematical.
This t d phase breaks the inversion symmetry and was predicted to support the existence of typeii weyl points 32,33. Extremely high magnetoresistance and conductivity in the type. 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 analytical and numerical study of the angular dependence of magnetoresistance in layered quasitwodimensional q2d metals is performed.
It is assumed that this field destroys the superconducting gap in each grain, such that all interesting effects considered in the paper are due to superconducting fluctuations. Inductive heads can give about a 1% effect, while magnetoresistance heads give about a 4% effect. The harmonic expansion analytical formulas for the angular dependence of fermisurface crosssection area in external magnetic field are obtained for various typical crystal symmetries. In 1988, baibich et al reported magnetoresistance effects of up to 50% at low. The origin of magnetism behavior of the 3d4f electrons, respectively.
We find results for diffusive walls that are thicker than the mean free path and for thinner ballistic walls. A spectacular anisotropy observed in cu is explained based on the nonspherical fermi surface of this metal in this chapter. From early measurements on noble metals to definitive characterization of localization effects in semiconductors to recent studies of topological materials, the magnetoresistive response provides an experimental technique to explore the fermi surface in detail, and to predict and craft physical properties. Magnetoresistance in metals by alfred brian pippard, 97805226605, available at book depository with free delivery worldwide. Introduction magnetoresistance changes of0resistance0bymagneticfield h. Negative magnetoresistance in dirac semimetal cd 3 as 2. Recently, negative longitudinal and positive inplane transverse magnetoresistance have been observed in most topological diracweyl semimetals, and some other topological materials.
We are going to treat the magnetoresistance of metals in a quite general and simple manner. This model permitted to explain satisfactorily all the data obtained in 7. The magnetoresistance was investigated from 10 to 290 k, revealing both intrinsic. All real metals, however, show a positive magnetoresistance. Dec 04, 2010 open library is an open, editable library catalog, building towards a web page for every book ever published.
The magnetic field intensity for figure 1 was 23,500 oe, or 2. Magnetoresistance in metals cambridge studies in low. Here we report the coexistence of ferroelectricity and. Kapitza reported magnetoresistance as increasing linearly with field strength for polycrystalline samples in 19294. Magnetoresistance of granular superconducting metals in a. The magnetization, electric resistivity, and magnetoresistance properties of pd 2 mn 1. Examples ofmetals displaying this behavior are bi, sb, w, and mo.
Magnetoresistance results from distortion of the trajectories of the current carriers in a magnetic field. This is the saturation field strength of a conventional iron core electromagnet. Pdf magnetoresistance of granular superconducting metals in. Extremely high magnetoresistance and conductivity in the. Giant magnetoresistance gmr is another type of magnetoresistance mr which is observed in magnetic multilayers and is much larger than the amr of the ferromagnetic metals. Under the magnetic field of 7 t, a maximum mr magnitude of 8. First published in 1989, this book contained the first systematic account of magnetoresistance in metals, the study of which has provided solidstate physicists with much valuable information about electron motion in metals. Magnetoresistance in real metals 8 dynamics of an electron historical note 18 effective path and dc conductivity 19 comments on the conductivity formula 22 1 application to a free electron gas with catastrophic scattering 22 2 kohlers rule 23 3 the magnetoresistance is normally positive 24 4 onsagers reciprocal relations 26. Gluzinski simple method of calculating the magnetoresistance effect in metals 3 equation 10 is examined below when the quantum properties ofv and dv dt are taken into account.
Giant magnetoresistance gmr is a quantum mechanical magnetoresistance. This meansthatdynamicalvariablesof10aretransformed into a quantummechanicaloperator form. Thomson, honored as lord kelvin, was noted for his engineering contributions in addition to his scientific achieve ments. Pdf domainwall magnetoresistance in antiferromagnetic. Wte 2 is a t d type of transitionmetal dichalcogenide space group pnm2 1 with a tungsten chain along the a axis, as shown in fig. The sources of insight are the effect of magnetic fields on resistivity, and the relationship that has to. Magnetoresistance in intercalated transition metals. Intrinsic magnetoresistance in threedimensional dirac materials. Pdf magnetoresistance of granular superconducting metals. However, genuine ferroelectricity with electrical dipolar switching has not yet been attained experimentally in conducting materials, especially the ones possessing magnetic responses.
The sources of insight are the effect of magnetic fields on resistivity, and the relationship that has to conducting electron orbital angular momentum. The chemical vapor deposition technique was adopted to synthesize the amorphous carbon thin films. A brief introduction to giant magnetoresistance liu chang1, min wang1, lei liu1, siwei luo2, pan xiao1, 1hycorelle co. On the other hand, while the touching points of conduc. Magnetoresistance in metallic ferroelectrics acs applied. Gatetunable negative longitudinal magnetoresistance in the. Get magnetoresistance in metals pdf file for free on our ebook library. Multiple mechanisms for this magnetoresistance phenomenon have been theoretically proposed, but experimentally it is unclear how to identify which mechanism is responsible in a particular sample or how to make a clean. We compute the dwmr when the current is perpendicular to the wall for several different spin structures with various dw orientations. Intrinsic magnetoresistance in threedimensional dirac. Electron mean free path 10100 nm must be greater than interlayer separation currentperpendicular. Magnetoresistance has a history of revealing key electronic characteristics of materials. There are a variety of effects that can be called magnetoresistance.
The intensive recent investigations of topological semimetals have revealed a large number of semimetal compounds that exhibit very large nonsaturating magnetoresistance. Request the article directly from the author on researchgate. Matthew melissa physics 141a spring 20 1 giant magnetoresistance matthew melissa april 4, 20. This seemed a rather universal fact, and physicists at least in the former soviet union, where kapitza worked after cambridge called it the linear kapitzas law. Magnetoresistance of the fmnmnm lateral devices are found to be negligible. Ibm started using magnetoresistance in its read heads in 1992.
Gatetunable negative longitudinal magnetoresistance in. The curie temperature of the parent phase, martensitic transformation temperatures, and magnetic field dependence of the martensitic transformation temperatures were determined. The measured magnetoresistance of the nonlocal spin valve as a function of magnetic field is shown in figure. A very large magnetoresistance effect was discovered in the early nineties in manganese oxides which was coined colossal magnetoresistance cmr 4, 5. Giant magnetoresistance in layered magnetic materials. Magnetoresistance of some hexagonal closepacked metals. Anisotropic magnetoresistance in ferromagnetic 3d alloys. Giant magnetoresistance gmr is a quantum mechanical magnetoresistance effect observed in thin film structures composed of alternating ferromagnetic and. R h ey jxh proportional to e y must benegativefor negative charge carriers e y 0 quantum e ects daniele to oli december. Magnetoresistance is a general term for the changes in the components of the resistivity and conductivity tensors of materials caused by the application of. Magnetoresistance anisotropy of single crystal silver at 4. This is the explanation for the ferromagnetism among the d transition metals. Electron orbital angular momentum and magnetoresistance in metals.
The magnetoresistance of a granular superconductor in a strong magnetic field is considered. Hall e ect and magnetoresistance hall e ect and magnetoresistance predictions from the drude model magnetoresistance and hall coe cient magnetoresistance. Such magnetoresistance measurements allow the number of free carriers to be obtained experimentally, as well as allow mapping of the fermi surface etc. The other principle axis, the b axis, is perpendicular to the a axis 37,39. Thus, the nearly free electron model should not provide a good description of the fermi surface for the transition metals. Jun 04, 2019 magnetoresistance has a history of revealing key electronic characteristics of materials. Magnetoresistance is the tendency of a material preferably ferromagnetic to change the value of its electrical resistance in an externallyapplied magnetic field. Polar metals with ferroelectriclike displacements in metals have been achieved recently, half a century later than anderson and blounts prediction. Coils of wire are still used to write magnetic data, since a change in resistance does not cause a magnetic field.
Nonsaturating large magnetoresistance in semimetals pnas. The resistance of a ferromagnetic metal changes when one applies a magnetic field. Magnetoresistance article about magnetoresistance by the. Electron orbital angular momentum and magnetoresistance in. Multiple mechanisms for this magnetoresistance phenomenon have been theoretically proposed, but experimentally it is unclear how to identify which mechanism is responsible in a particular sample or. Giant magnetoresistance gmr is a quantum mechanical magnetoresistance effect observed in multilayers composed of alternating ferromagnetic and nonmagnetic conductive layers. Nonlinear to linear negative magnetoresistance mr was studied under the magnetic field ranging from. Oct 11, 2016 negative magnetoresistance in dirac semimetal cd 3 as 2. In these materials the electrical resistance can be changed several. Magnetic oscillations found in the susceptibility also manifest themselves in magnetoresistance at low temperatures. Magnetoresistance an overview sciencedirect topics.
Molecular orbital approach to magnetoresistance in metals. Electron orbital angular momentum and magnetoresistance. In these materials the electrical resistance can be changed several orders of magnitude by application of a large magnetic field. Free electron theory of metals, low temperatures, magnetoresistance. As the theory stands today, magnetoresistance in metals is ascribed. Nov 21, 2017 here we show that wp 2 exhibits extremely high conductivity and the highest magnetoresistance mr values yet observed in any compound with an extraordinarily large mean free path of 0.
Linear magnetoresistance in the lowfield limit in density. Magnetoresistance mr in general is nonzero and anisotropic. Here we present a quantum theory of intrinsic magnetoresistance for threedimensional dirac fermions at a. Negative magnetoresistance is the term given to the large decrease in the electrical resistance when certain systems are exposed to a magnetic.
By 1994, all read heads produced by ibm were using magnetoresistance. The origin of linear magnetoresistanceexotic or classical. Magnetoresistance in intercalated transition metals makiko0ogino, dept. In semiconductors the relative change in resistance. A large negative magnetoresistance nmr is anticipated in topological semimetals in parallel magnetic fields, demonstrating the chiral anomaly, a longsought highenergyphysics effect, in. The magnetoresistance effect is small at small magnetic flux densities. Giant negative magnetoresistance induced by the chiral anomaly in individual cd 3 as 2 nanowires. Anisotropic magnetoresistance an overview sciencedirect. The rare earth metals have a core which is small compared to interatomic distances and, for these metals, the actual fermi surface might be only a slight modification of the nearly free electron model. The 2007 nobel prize in physics was awarded to albert fert and peter grunberg for the discovery of gmr. Emeritus professor of physics, university of cambridge. Oct 16, 2018 the intensive recent investigations of topological semimetals have revealed a large number of semimetal compounds that exhibit very large nonsaturating magnetoresistance. Crystals free fulltext anomalous nonlinear to linear.