Quantitative Decoding of Interactions in Tunable Nanomagnet Arrays Using First Order Reversal Curves

To develop a full understanding of interactions in nanomagnet arrays is a persistent challenge, critically impacting their technological acceptance. This paper reports the experimental, numerical and analytical investigation of interactions in arrays of Co nanoellipses using the first-order reversal curve (FORC) technique. A mean-field analysis has revealed the physical mechanisms giving rise to all of the observed features: a shift of the non-interacting FORC-ridge at the low-HC end off the local coercivity HC axis; a stretch of the FORC-ridge at the high-HC end without shifting it off the HC axis; and a formation of a tilted edge connected to the ridge at the low-HC end. Changing from flat to Gaussian coercivity distribution produces a negative feature, bends the ridge, and broadens the edge. Finally, nearest neighbor interactions segment the FORC-ridge. These results demonstrate that the FORC approach provides a comprehensive framework to qualitatively and quantitatively decode interactions in nanomagnet arrays.

[1]  Kai Liu,et al.  Magnetization reversal and nanoscopic magnetic-phase separation in La1-xSrxCoO3 , 2005 .

[2]  H. Oepen,et al.  Multipolar ordering and magnetization reversal in two-dimensional nanomagnet arrays. , 2005, Physical review letters.

[3]  V. Crespi,et al.  Artificial ‘spin ice’ in a geometrically frustrated lattice of nanoscale ferromagnetic islands , 2006, Nature.

[4]  William J. Gallagher,et al.  Development of the magnetic tunnel junction MRAM at IBM: From first junctions to a 16-Mb MRAM demonstrator chip , 2006, IBM J. Res. Dev..

[5]  S. Bader.  Colloquium: Opportunities in Nanomagnetism , 2006 .

[6]  O. Heinonen,et al.  Spectral analysis of topological defects in an artificial spin-ice lattice. , 2012, Physical review letters.

[7]  S. Bader.  Opportunities in Nanomagnetism , 2007 .

[8]  A. Yelon,et al.  First-order reversal curve diagrams of magnetic entities with mean interaction field: A physical analysis perspective , 2008 .

[9]  Mayergoyz,et al.  Mathematical models of hysteresis. , 1986, Physical review letters.

[10]  J. Bokor,et al.  Detecting single nanomagnet dynamics beyond the diffraction limit in varying magnetostatic environments , 2011 .

[11]  A. Kikitsu,et al.  Patterned magnetic recording media , 2006, Asia-Pacific Magnetic Recording Conference 2006.

[12]  V. Mathet,et al.  Magnetization Reversal in Arrays of Perpendicularly Magnetized Ultrathin Dots Coupled by Dipolar Interaction , 1998 .

[13]  A. Yelon,et al.  Magnetic Behavior of Ni/Cu Multilayer Nanowire Arrays Studied by First-Order Reversal Curve Diagrams , 2008, IEEE Transactions on Magnetics.

[14]  T. Schrefl,et al.  First order reversal curve studies of permanent magnets , 2012 .

[15]  Jie Li,et al.  Perpendicular magnetization and generic realization of the Ising model in artificial spin ice. , 2012, Physical review letters.

[16]  R. W. Dave,et al.  A 4-Mb toggle MRAM based on a novel bit and switching method , 2005, IEEE Transactions on Magnetics.

[17]  F Pázmándi,et al.  Reversal-field memory in the hysteresis of spin glasses. , 2002, Physical review letters.

[18]  Alexandru Stancu,et al.  Micromagnetic and Preisach analysis of the First Order Reversal Curves (FORC) diagram , 2003 .

[19]  D. Gilbert,et al.  Fingerprinting Inhomogeneities in Recording Media Using the First-Order Reversal Curve Method , 2011, IEEE Transactions on Magnetics.

[20]  Chengguo Jia,et al.  Monodisperse FePt Nanoparticles and Ferromagnetic FePt Nanocrystal Superlattices , 2014 .

[21]  Ivan K. Schuller,et al.  First-order reversal curve measurements of the metal-insulator transition in VO 2 : Signatures of persistent metallic domains , 2009 .

[22]  Angular Dependence of Vortex Annihilation Fields in Asymmetric Co Dots , 2009, 0906.3877.

[23]  A. Stancu,et al.  What does a first-order reversal curve diagram really mean? A study case: Array of ferromagnetic nanowires , 2013 .

[24]  Qi Lu,et al.  Memory Effect in Magnetic Nanowire Arrays , 2011, Advanced materials.

[25]  R. Cowburn,et al.  Room temperature magnetic quantum cellular automata , 2000, Science.

[26]  Olle Heinonen,et al.  Recording potential of bit-patterned media , 2006 .

[27]  Caroline A. Ross,et al.  First-order reversal curve diagram analysis of a perpendicular nickel nanopillar array , 2005 .

[28]  O. Hellwig,et al.  Magnetization reversal of Co/Pt multilayers: Microscopic origin of high-field magnetic irreversibility - eScholarship , 2004 .

[29]  D. Allwood,et al.  Enhanced Longitudinal Magnetooptic Kerr Effect Contrast in Nanomagnetic Structures , 2007, IEEE transactions on magnetics.

[30]  S. Jain,et al.  Spin re-orientation in magnetostatically coupled Ni80Fe20 ellipsoidal nanomagnets , 2010, Nanotechnology.

[31]  A Imre,et al.  Majority Logic Gate for Magnetic Quantum-Dot Cellular Automata , 2006, Science.

[32]  Andrew P. Roberts,et al.  Characterizing interactions in fine magnetic particle systems using first order reversal curves , 1999 .