Navigation Links
Size matters in the giant magnetoresistance effect in semiconductors

In a paper appearing in Nature's Scientific Reports, Dr. Ramesh Mani, professor of physics and astronomy at Georgia State University, reports that a giant magnetoresistance effect depends on the physical size of the device in the GaAs/AlGaAs semiconductor system.

Giant magnetoresistance indicates a large change in the electrical resistance with the application of a small magnetic field. This effect can be used to detect the presence of small magnetic fields. Magnetic sensors based on this concept are used to read out information stored in magnetic particles on rotating platters in computer hard disks. Other types of magnetic sensors are also used in brushless electric motors within cooling fans in computers, and as wheel speed sensors in some automobiles. Semiconductors are materials with electrical characteristics that fall between those of insulators and metals. Such materials are widely used, especially in electronics.

In research that is supported by grants from the U.S. Department of Energy and the U.S. Army Research Office, Mani studied the magnetoresistance in flat, very thin sheets of electrons in the ultra high quality GaAs/AlGaAs semiconductor with his colleagues Annika Kriisa from Emory University and Werner Wegscheider from the ETH-Zurich in Switzerland.

The researchers found that the change in the resistance or resistivity with the magnetic field depends on the size of the device. They demonstrated that, under the application of a magnetic field, wide devices develop a smaller and quicker change, while small devices develop a bigger but slower change in the resistivity. The resistance or resistivity of a material to the flow of electricity is a technologically important property, especially in semiconductors.

In a typical semiconductor, the disorder is so strong that electrons undergo many collisions over a short distance - distance much less than millimeters. Then, the edges or walls of the device have no influence on measured properties because the electrons lose memory of one edge or wall by the time they get to another.

The strong sensitivity of the magnetoresistance to the size of the device observed in this research indicates that scattering with the walls of the device might be making a substantial contribution to electron scattering. This result testifies to the high quality of the semiconductor used in this research, produced by Prof. Werner Wegscheider at ETH-Zurich in Switzerland.

This research team developed a model to understand the observations and deduced that when the semiconductor system becomes of even better quality, the change in the resistance under the application of a magnetic field will become even bigger. Indeed, the change might become so big that the resistance vanishes entirely in the small magnetic field.


Contact: LaTina Emerson
Georgia State University

Related biology technology :

1. Jeffrey Toobin Joins Gateway Public Schools for the 2013 Matters of the Mind Luncheon
2. Management Matters Series Starts with “Lab Budgeting 101”
3. Aims to Raise Awareness and Coordinate Care Between Mental and Physical Health
4. Express Diagnostics to Raise Funds for American Cancer Society During Blue Earth’s Giant Days Parade
5. Researchers untangle molecular pathology of giant axonal neuropathy
6. Berkeley Lab researchers use metamaterials to observe giant photonic spin hall effect
7. GLM Displays Introduces New Banner Stand – 10’ Tall “Giant Mosquito”
8. VIASPACE Chairman and CEO Attend EUEC 2013, Giant King Grass Prominently Featured in Convention Exhibit Hall
9. A giant step in a miniature world: UZH researcher measures the electrical charge of nano particles
10. Exotic particles, chilled and trapped, form giant matter wave
11. SoundConnect Responds to Increased, Cost-Effective Unified Communications Demands Through Agent Partnership Program
Post Your Comments:
(Date:11/25/2015)... 2015 Studies reveal the differences ... and pave the way for more effective treatment for one ...   --> --> ... problems in cats, yet relatively little was understood about the ... have been conducted by researchers from the WALTHAM Centre for ...
(Date:11/25/2015)...  Neurocrine Biosciences, Inc. (Nasdaq: NBIX ) announced ... of Neurocrine Biosciences, will be presenting at the 27th ... York . .   ... minutes prior to the presentation to download or install ... be available on the website approximately one hour after ...
(Date:11/25/2015)... ... November 25, 2015 , ... A long-standing partnership between ... (OPBAP) has been formalized with the signing of a Memorandum of Understanding. , ... leaders Capt. Karl Minter and Capt. Albert Glenn Tuesday, November 24, 2015, at ...
(Date:11/25/2015)... , November 25, 2015 ... Report is a professional and in-depth study on ...      (Logo: ) , ... the industry including definitions, classifications, applications and industry ... for the international markets including development trends, competitive ...
Breaking Biology Technology:
(Date:11/20/2015)... -- NXTD ) ("NXT-ID" or the "Company"), ... commerce market and creator of the Wocket® smart wallet, ... interviewed on The RedChip Money Report television ... Bloomberg Europe , Bloomberg Asia, Bloomberg Australia, and ... ) ("NXT-ID" or the "Company"), a biometric authentication company ...
(Date:11/19/2015)... -- Although some 350 companies are actively involved in molecular ... according to Kalorama Information. These include Roche Diagnostics, Hologic, Abbott ... of the 6.1 billion-dollar molecular testing market, according to ... Diagnostic s .    ... one company and only a handful of companies can ...
(Date:11/18/2015)... , November 18, 2015 ... published a new market report titled  Gesture Recognition Market ... Forecast, 2015 - 2021. According to the report, the global gesture ... is anticipated to reach US$29.1 bn by 2021, at ... North America dominated the global ...
Breaking Biology News(10 mins):