Magnetic Memory: Data Storage and Nanomagnets

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Magnetic Memory: Data Storage and Nanomagnets. Mark Tuominen Professor of Physics. 20 GB. 40 GB. 10 GB. 2001. 2002. 2004. Hard drive Magnetic data storage. 80 GB. 160 GB. 2006. 2007. Review. Data Storage. Example: Advancement of the iPod. Uses nanotechnology!. anisotropy axis - PowerPoint PPT Presentation

Text of Magnetic Memory: Data Storage and Nanomagnets

  • Magnetic Memory:Data Storage and NanomagnetsMark Tuominen Professor of Physics

  • Data Storage. Example: Advancement of the iPodUses nanotechnology!Review

  • Ferromagnetuniform magnetizationElectron magnetic moments ("spins")

    Aligned by "exchange interaction"Bistable:Equivalentenergy for "up" or "down"states

  • Ferromagnets are used to store data?Ferromagnet with unknown magnetic state

  • Magnetic Data StorageA computer hard drive stores your data magneticallyDiskNSdirection of disk motionWriteHeadNScurrent

  • Scaling Down to the NanoscaleIncreases the amount of data stored on a fixed amount of real estate !Now ~ 100 billion bits/in2, future target more than 1 trillion bits/in2

  • Improving Magnetic Data Storage TechnologyThe UMass Amherst Center for Hierarchical Manufacturing is working to improve this technology

    Y. Sonobe, et al., JMMM (2006) 1 bit

  • Filling the Template: Making Cobalt Nanorods by Electrochemical Depositionmetal

  • Binary Representation of Dataone bit1 or 0only 2 choicesn bits has 2n choicesFor example, 5 bits has 25 = 32 choices...more than enough to represent all the letters of the alphabet

  • Binary representationof lower case letters5-bit "Super Scientist" code:

    ex: k = 01011SNSNSNSSOR(Coding Activity: Use attractive and repulsive forces to "read" the magnetic data!)

    Sheet1

    CharacterASCII code"SS"code

    a110000100001

    b110001000010

    c110001100011

    d110010000100

    e110010100101

    f110011000110

    g110011100111

    h110100001000

    i110100101001

    j110101001010

    k110101101011

    l110110001100

    m110110101101

    n110111001110

    o110111101111

    p111000010000

    q111000110001

    r111001010010

    s111001110011

    t111010010100

    u111010110101

    v111011010110

    w111011110111

    x111100011000

    y111100111001

    z111101011010

    ASCII = American Standard Code for Information Exchange

    "SS" = Science Saturday

    Sheet2

    Sheet3

  • NEW! Multi-State Representation of DataDiskWriteHead==01direction of disk motion1032"CLUSTERS"

  • M = -3M = -1M = +1M = +33-Nanomagnet ClusterImaged with a MFM(Magnetic Force Microscope)Just accomplished summer 2007 in the CHM!

  • "Multi-state" representationof lower case letters1032What is the word?

    Sheet1

    CharacterASCII code"SS"code

    a1100001001

    b1100010002

    c1100011003

    d1100100010

    e1100101011

    f1100110012

    g1100111013

    h1101000020

    i1101001021

    j1101010022

    k1101011023

    l1101100030

    m1101101031

    n1101110032

    o1101111033

    p1110000100

    q1110001101

    r1110010102

    s1110011103

    t1110100110

    u1110101111

    v1110110112

    w1110111113

    x1111000120

    y1111001121

    z1111010122

    ASCII = American Standard Code for Information Exchange

    "SS" = Science Saturday

    Sheet2

    Sheet3

  • The Bistable Magnetization of a Nanomagnet A single-domain nanomagnet with a single easy axis (uniaxial anisotropy) has two stable magnetization states

    topviewshorthandzorHMzMzBistable. Ideal for storing data - in principle, even one nanomagnet per bit.hysteresis curveE = K1sin2Hswitching field

    It is always useful to start the introduction with something simple such that anyone could get something out of the talk. This page introduces the concept of a single-domain nanomagnet as a basic element for data storage. Note that the animation helps to tell the story in a linear and logical way. Please add actual diagrams of the double well for the three fields shown.For the published part of our results, we chose another approach to electrodeposite the Co magnetic cluster for our experiments. This procedure had been studied thougrhtouly by my colleague Dr. Ursache in our lab. The deposition electrolyte is carefully tuned to pH6, And we used PRECD. the voltage we applied to the working electrode in the potentialstat ECD cell can be timed to two phases. Each of the repeating phases is 10 ms long. In the pulse phase, the voltage we put on the working electrode is 1 V to the standard reference electrode. The Co atoms are deposited into the pattern. But not all of the Co atoms can land on the perfect crystal lattice points. During the reverse cycle, the voltage we put on the working electrode is 0.35 V. This will remove the loosely bonded Co atoms back into the solution.It is always useful to start the introduction with something simple such that anyone could get something out of the talk. This page introduces the concept of a single-domain nanomagnet as a basic element for data storage. Note that the animation helps to tell the story in a linear and logical way. Please add actual diagrams of the double well for the three fields shown.