A highly sensitive flexible magnetic sensor based on the anisotropic magnetoresistance effect is fabricated. Tunnelling anisotropic magnetoresistance due to antiferromagnetic. T can be achieved by an elliptically shaped sensor layout. The parameters of the sensor layout and sensitivity considerations are discussed. Inplane and outofplane anisotropic magnetoresistance in. Sep 10, 2014 a tunnelling anisotropic magnetoresistance tamr has been previously reported in devices with an antiferromagnetic afm metal electrode on one side and a nonmagnetic metal on the other side of. To investigate the origin of the spinvalvelike signal in polymer spin valve with a vertical structure of nifep3htaloxco, the magnetic response measurements in the rotated magnetization direction were established in different. The observation of induced ferromagnetism in pt via amr is further supported by density. Applying current along x axis with current density of jc x, phe and amr probes the transverse and longi. Research progress in anisotropic magnetoresistance springerlink. Anisotropic magnetoresistance in antiferromagnetic sr 2 iro.
Tunneling anisotropic magnetoresistance is promising for next generation memory devices but limited by the low efficiency and functioning temperature. Remote detection of nuclear magnetic resonance with an. Apr 06, 2015 spinorbit effects in ferromagnets, the anomalous hall effect and the anisotropic magnetoresistance, generate spin currents in addition to the charge currents with which they are traditionally associated. The conductance of feterephthalic acid tpafe singlemolecule junctions is measured and a giant singlemolecule tunneling anisotropic magnetoresistance tamr up to 53% is observed at room temperature.
Highly sensitive flexible magnetic sensor based on. Anisotropic magnetoresistance in manganite films article in journal of magnetism and magnetic materials 272. Besides the fundamental significance, our finding might. These abnormal magnetoresistance behaviors in zrsis can be. Large roomtemperature tunneling anisotropic magnetoresistance and electroresistance in single ferromagnetnb. We derive the general expression of the anisotropic magnetoresistance amr ratio of ferromagnets for a relative angle between the magnetization direction and the current direction. This combination of benefits is unprecedented, and it is not achievable using any other existing magnetic sensor technologies, including anisotropic magnetoresistance amr, giant magnetoresistance gmr, or the hall effect. View the article pdf and any associated supplements and figures for a period of 48 hours. Anisotropic magnetoresistance of cenisn sciencedirect.
Tunneling anisotropic magnetoresistance driven by magnetic phase transition. Both the polarity and magnitude of the phase transition tunneling anisotropic. Anisotropic magnetoresistance article about anisotropic. A very large magnetoresistance effect was discovered in the early nineties in manganese oxides which was coined colossal magnetoresistance cmr 4, 5. In the present case, however, magnetic scattering is dominant. On the other hand, the positive magnetoresistance is found to become dominant with the decrease of temperature for h jib and caxis in the transverse configuration j.
Anisotropic magnetoresistance occurs in certain ferrous materials and can be applied as a thin strip to become a resistive element. Tunneling anisotropic magnetoresistance driven by magnetic phase. This study investigates the anisotropic magnetoresistance amr of epitaxial tetragonal antiferromagnetic bimetallic films. Inductive heads can give about a 1% effect, while magnetoresistance heads give about a 4% effect. Anomalous anisotropic magnetoresistance in topological. Anisotropic magnetoresistance how is anisotropic magnetoresistance abbreviated. Magnetoresistance and its applications anisotropic magnetoresistance in ferromagnetic alloys on globalspec. Anomalous anisotropic magnetoresistance of antiferromagnetic. The measurements at liquid nitrogen temperature reveal negative magnetoresistances up to 28% for modest magnetic fields 250 mt applied within. Related with the detection of weak magnetic fields, the anisotropic magnetoresistive amr effect is widely utilized in sensor applications. Calibration of offtheshelf anisotropic magnetoresistance. Pdf anisotropic magnetoresistance in perovskite manganites. Here, we report the observation of extremely large magnetoresistance as 3.
Anisotropic magnetoresistance in an antiferromagnetic. The reason for using anisotropic magnetoresistive sensors amr as an alternative to the lisa path. Hoffmann information stored in magnetic materials is university of illinois urbanachampaign often readout by measuring changes in. There are a variety of effects that can be called magnetoresistance. The longitudinal magnetoresistance jijh is small in magnitude for the magnetic field hjlb and caxis. To investigate the origin of the spinvalvelike signal in polymer spin valve with a vertical structure of nifep3htaloxco, the magnetic response measurements in the rotated magnetization direction were established in different welldesigned. Giant magnetoresistance gmr is a quantum mechanical magnetoresistance effect observed in multilayers composed of alternating ferromagnetic and nonmagnetic conductive layers. Anisotropic magnetoresistance in nifebased polymer spin. Adaptive thermocompensation of magnetoresistive sensoradaptyvi magnetorezistyvinio jutiklio temperaturine kompensacija. Besides, the amrtype hmc100120 presents the lowest noise level amongdi. The stm break junction is equipped with an external magnetic field either parallel or perpendicular to the electron transport direction. Large roomtemperature tunneling anisotropic magnetoresistance and.
In this article, we summarize the recent advances in amr, including traditional permalloy amr, tunnel amr, ballistic amr, coulomb blockade. Jun 19, 20 anisotropic magnetoresistance amr is an important physical phenomenon that has broad application potential in many relevant fields. Thomsons experiments 4 are an example of amr, 7 a property of a material in which a dependence of electrical resistance on the angle between the direction of electric current and direction of. Here, we show that singlemolecule junctions based on nickel electrodes and benzene molecules can yield a signi. Based on ab initio calculations, we associate the origin of the phenomenon with large anisotropies in the relativistic electronic structure.
We here use the twocurrent model for a system consisting of a spinpolarized conduction state s and localized d states d with spinorbit interaction. Multiplestable anisotropic magnetoresistance memory in. They cover the sophisticated fields of measurement, such as navigation systems, by supporting gps measurements or drones for attitude determination 2,3,4. Large enhancement of anisotropic magnetoresistance and. Anisotropic magnetoresistance in antiferromagnetic sr 2. The continuously varying amr provides means for the electrical readout of multiplestable antiferromagnetic memory states, which we set by heatassisted magnetorecording. In these materials the electrical resistance can be changed several orders of magnitude by application of a large magnetic field. The observation of induced ferromagnetism in pt via amr is further supported by density functional theory dft calculations and various control measurements including insertion. Spin transfer torques generated by the anomalous hall. Anisotropic magnetoresistance amr the resistance of a thin permalloy film is shown here as a function of the angle of an applied external field. We report pointcontact measurements of anisotropic magnetoresistance amr in a single crystal of antiferromagnetic mott insulator sr2iro4. When the electric current is still along the b axis but the magnetic field is parallel to the current, the mr ratio is suppressed and is around 10 4 % in 9 t field and 2 k, as shown. Spinorbit effects in ferromagnets, the anomalous hall effect and the anisotropic magnetoresistance, generate spin currents in addition to the charge currents with which they are traditionally associated.
Various sensor designs and electronic evaluation circuits have been developed to overcome temperature dependence, offset, and hysteresis, see, for example refs. Namely, the magnetoresistance reflects the anisotropy of magnetic scattering. Giant singlemolecule anisotropic magnetoresistance at room. Sun2 1beijing national laboratory for condensed matter physics, institute of physics, chinese academy. Recently intensive efforts have been devoted to the emerging field of antiferromagnetic afm spintronics, where ferromagnetic electrodes are substituted by antiferromagnets. The junctions with only one ferh magnetic electrode show a magnetoresistance ratio up to 20% at room temperature. The temperature dependence of anisotropic magnetoresistance in manganites exhibits a peak near the magnetic ordering temperature which differs dramatically from the ones in 3d ferromagnetic metals. The magnetic field response of the transport properties of condensed matter, especially the magnetoresistance mr such as the giant magnetoresistance in magnetic multilayers and colossal magnetoresistance in manganites 1,2, gives information about the characteristics of the fermi surface 3 and provides promising candidates for magnetic memory or other spintronic. The first hard disk drives hdds date back to the 1950s. The measurements at liquid nitrogen temperature reveal negative magnetoresistances up to 28% for modest magnetic.
Anisotropic magnetoresistive amr magnetometers are used in a variety of applications for angle measuring, attitude determination, and even magnetic field observations for space science. Anisotropic magnetoresistance effect field sensors. Our experimental and theoretical study of the noncrystalline and crystalline components of the anisotropic magnetoresistance amr in ga,mnas is aimed at exploring the basic physical aspects of this relativistic transport effect. Pdf we have summarized some important results of the anisotropic transport properties of the prototypical manganite la1xcaxmno3 as. The anisotropic magnetoresistive effect of dcsputtered ni 81%fe 19% films has been increased up to. Afm spintronics, where ferromagnetic electrodes are substituted by antiferromagnets. Charge current manifest its anisotropic properties by the planar hall effect phe and anisotropic magnetoresistance amr, which are captured by ec xy j c x. Ibm started using magnetoresistance in its read heads in 1992.
An anomalous amr effect with additional peaks is observed. The 2007 nobel prize in physics was awarded to albert fert and peter grunberg for the discovery of gmr. Spin transfer torques generated by the anomalous hall effect. Elsevier physica b 230232 1997 690694 anisotropic magnetoresistance of cenisn y. 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. Figure 2 in plane magnetoresistance of sample 1 200 nm thick bi2se3 film. Research progress in anisotropic magnetoresistance. In this article, we summarize the recent advances in amr, including traditional permalloy amr, tunnel amr, ballistic amr, coulomb blockade amr, anomalous amr, and. The noncrystalline amr reflects anisotropic lifetimes of the holes due to polarized mn impurities while the crystalline amr is associated with valence band warping.
Negative magnetoresistance is the term given to the large decrease in the electrical resistance when certain systems are exposed to a magnetic. We report pointcontact measurements of anisotropic magnetoresistance amr in a single crystal of antiferromagnetic afm mott. Sun2 1beijing national laboratory for condensed matter physics, institute of physics, chinese academy of sciences, beijing 100190, peoples republic of china. Giant singlemolecule anisotropic magnetoresistance at.
The anisotropic magnetoresistance amr sensor undergoes an increase in resistance when current is applied in the same direction as the magnetic field and a decrease in resistance when the current is applied at a 90 degree angle to the magnetic field or force. H is the resistivity in the presence of a magnetic. Magnetoresistance is the tendency of a material often ferromagnetic to change the value of its electrical resistance in an externallyapplied magnetic field. You are advised to consult the publishers version publishers pdf if you wish to. Such magnetoresistance measurements allow the number of free carriers to be obtained experimentally, as well as allow mapping of the fermi surface etc. Anisotropic magnetoresistance amr magnetometers springerlink. Gmr is kind of like magnetoresistance on steroids, and was indeed a giant step for mankind when it was discovered in. An external file that holds a picture, illustration, etc. The independent control of two magnetic electrodes and spincoherent transport in magnetic tunnel junctions are strictly required for tunneling. By 1994, all read heads produced by ibm were using magnetoresistance. University of groningen magnon planar hall effect and. Anisotropic magnetoresistive amr based magnetometers are used in devices as varied as global positioning systems to provide dead reckoning capability and in automotive ignition systems to provide. The underlying mechanism for the giant amr is an indispensable combination of atomic scale giantmrlike effect and.
A limit of detection of 150 nt is observed and excellent deformation stability is achieved after wrapping of the flexible sensor, with bending radii down to 5 mm. The phenomenon of anisotropic magnetoresistance in materials and ferromagnetic metals was discovered by lord kelvin in 1857, and is an example of a galvanomagnetic effect in conductors. T and mr of nbsb 2 is significantly dependent on the electric current and magnetic field direction. On the other hand, the magnetoresistance above 4 k is found to. View enhanced pdf access article on wiley online library html view download pdf for offline viewing. Anisotropic magnetoresistance in antiferromagnetic sr2iro4. Giant anisotropic magnetoresistance and nonvolatile memory in. The pointcontact technique is used here as a local probe of magnetotransport properties on the nanoscale. Both the polarity and magnitude of the phase transition tunneling anisotropic magnetoresistance can be modulated by interfacial engineering at the ferhmgo interface. The term giant magnetoresistance gmr has come to be associated with certain thin metallic multi. Large enhancement of anisotropic magnetoresistance and thermal stability in tanifeta trilayers with interfacial pt addition y. For hrla, the magnetoresistance is negative for any current direction. Anisotropic magnetoresistance in ube sciencedirect. Surface state anisotropic magnetoresistance in proximity magnetized topological insulators n.
These effects allow for the injection of a spin current into layers perpendicular to the electrical current flow. Inplane and outofplane anisotropic magnetoresistance in ni80fe20 thin. Thus, amr is one of the most attractive research directions in material science to date. Anisotropic magnetoresistance components in ga,mnas. Sep 21, 2016 anisotropic magnetoresistive amr based magnetometers are used in devices as varied as global positioning systems to provide dead reckoning capability and in automotive ignition systems to provide. Tunneling anisotropic magnetoresistance in a magnetic tunnel junction with halfmetallic electrodes. Tunneling anisotropic magnetoresistance driven by magnetic.
We report tunneling anisotropic magnetoresistance tamr due to the rotation of antiferromagnetic moments of an insulating coo layer. First relying on induction coils, later versions of hard disk drives capitalized on new technologies and knowledge, incorporating anisotropic magnetoresistance amr, or mr and, a few years later, giant magnetoresistance gmr. Coils of wire are still used to write magnetic data, since a change in resistance does not cause a magnetic field. Large roomtemperature tunneling anisotropic magnetoresistance. We find that the sign of the noncrystalline amr is determined by the form of spinorbit coupling in the host band and by the relative strengths of the nonmagnetic and magnetic. Enhanced magnetoresistance in molecular junctions by. We are going to treat the magnetoresistance of metals in a quite general and simple manner. Anisotropic magnetoresistance amr is an important physical phenomenon that has broad application potential in many relevant fields. Maezawad department of physics, faculty of science, osaka university, toyonaka 560, japan b faculty of science, hirsohima university, higashihiroshima 739, japan c faculty of integrated. Anisotropic magnetoresistance is generally observed in normal metals and analyzed by taking into account of the topology of the fermi surface. Anisotropic magnetoresistance in manganite films request pdf. Lenczowski department of physics, eindhoven university of technology, p. Anomalous anisotropic magnetoresistance of antiferromagnetic epitaxial bimetallic films.
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