Effects of the individual particle relaxation time on superspin glass dynamics

Effects of the individual particle relaxation time on superspin glass dynamics.

Mikael Svante Andersson, Jose Angel De Toro, Su Seong Lee, Peter S. Normile, Per Nordblad, and Roland Mathieu

Phys. Rev. B 93, 054407 (2016)

MIRM vs temperature using a perturbation field of 40 A/m and th=300 s for several halting temperatures; Th=50, 60, 70, 80, 90, 100, and 110 K for (a) RCP6 and (b) RCP8. (c) Selected MIRM(T) curves for RCP6 and RCP8 plotted together. Data for RCP8 is adapted from Ref. [15].

Tunable exchange bias in dilute magnetic alloys – chiral spin glasses

Tunable exchange bias in dilute magnetic alloys – chiral spin glasses

Matthias Hudl, Roland Mathieu and Per Nordblad

Scientific Reports 6, 19964 (2016)

(a) The central part of M vs. H loops after cooling the sample in H_FC to 5 K, and measure the hysteresis loop on decreasing the field to – H_FC and back to +H_FC. The insets show the field dependence of the parameter H_sw1, H_sw2, (right) and ΔM (left) in the H_FC range 1 to 9 T. (b) Full hysteresis loops measured at 5 K from 0 to 14, 14 to −14 and then back +14 T. The inset shows the central part of the loop and the fields H_sw1 and H_sw2 are marked. The jump and definition of the excess magnetization, ΔM, is indicated in the main frame. (c,d) The central part of the hysteresis loops measured after field cooling (c) and zero field cooling (d) in fields up to 5 T at 5 K. The arrows indicate the initial field sweep direction. (Red loops- positive initial fields, blue loops - negative initial fields).

Spin-glass-like freezing of inner and outer surface layers in hollow γ-Fe2O3 nanoparticles

Spin-glass-like freezing of inner and outer surface layers in hollow γ-Fe2O3 nanoparticles.

Hafsa Khurshid, Paula Lampen-Kelley, Òscar Iglesias, Javier Alonso, Manh-Huong Phan, Cheng-Jun Sun, Marie-Louise Saboungi & Hariharan Srikanth

Scientific Reports 5, 15054 (2015) 

Snapshots of the outer and inner surface spin configurations subject to varying magnetic fields (a) h = 100 (the maximum positive applied field), (b) h = 0 (remanence at the upper branch), (c) h = −25 (near the negative coercive field), and (d) h = −100 (the maximum negative applied field). Spins have been colored with a gradient from dark-red/dark-blue (outer/inner surface) for spins along the field direction to yellow/green (outer/inner surface) for spins transverse to the field direction. Only a slice of the spin configurations of a hollow nanoparticle close to the central plane and perpendicular to the field direction is shown.

EB in spin glass/ferromagnet bilayers

Cooling field and temperature dependent exchange bias in spin glass/ferromagnet bilayers.
W. B. Rui, Y. Hu, A. Du, B. You, M. W. Xiao, W. Zhang, S. M. Zhou, J. Du
Scientific Reports 5, 13640 (2015)

(a) The M-H hysteresis loops measured under H_FC = 0.2 kOe and 50 kOe at T = 2 K for a Fe₁₁Au₈₉(50 nm)/FeNi(5 nm) sample, (b) the calculated M-H hysteresis loops under H_FC = 0.2 kOe and 50 kOe at T = 2.6 K for the SG/FM bilayers, and the experimental (c) and calculated (d) cooling field dependences of low-temperature H_E and H_C.

SG behavior in dilute dipolar Ising system

Low-temperature spin-glass behavior in a diluted dipolar Ising system.

Juan J. Alonso

Phys. Rev. B 91, 094406 (2015)

Semilog plots of q̃2(t0,t) and q2 vs time t (in MC sweeps) for DIS systems with concentration x=0.35 running at the lowest temperature Tn for the values of L indicated in the figure. T=0.075(T=0.05) for L=10(L=8).

 

Glas transition in dipolar magnets?

Unreachable glass transition in dilute dipolar magnet.
A. Biltmo & P. Henelius ncomms1857.pdf (application/pdf Object)

The experimental data (black dots) are from Quilliam et al.¹³, whereas red lines are best fits to equation (3) at temperatures 0.10, 0.11, 0.12, 0.14, 0.15, 0.17 and 0.20 K from left to right.

Superantiferromagnetism in NPs

Size-induced superantiferromagnetism with reentrant spin-glass behavior in metallic nanoparticles of TbCu2.
C. Echevarria-Bonet, D. P. Rojas, J. I. Espeso, J. Rodríguez Fernández,1 L. Rodríguez Fernández, P. Gorria, J. A. Blanco, M. L. Fdez-Gubieda, E. Bauer, G. André, and L. Fernández Barquín
Phys. Rev. B 87, 180407 (2013)

Thermomagnetic DC-susceptibility ZFC curves obtained with magnetic fields, 1 kOe H 10 kOe, where
the evolution from AF to SG state can be observed. A FC curve is also plotted at H = 1 kOe to evidence the irreversibility. Inset (bottom): Linear Tf variation vs H2/3. Inset (top): ZFC DC susceptibility of the alloy at a pressure P = 1.1 GPa.

Exchange bias in manganite NPs

Evidence of exchange bias effect and surface spin glass ordering in electron doped Sm0.09Ca0.91MnO3 nanomanganites.
S. K. Giri, A. Poddar, and T. K. Nath
J. Appl. Phys.112, 113903 (2012)

The schematic representation of the phenomenological model forbulk manganites and the corresponding nanograins, described in the text.

SG behavior and Kondo effect

Kondo effect and spin-glass behavior of dilute iron clusters in silver films.
W. T. Herrera, Y. T. Xing, S. M. Ramos, P. Munayco, M. B. Fontes, E. M. Baggio-Saitovitch, and F. J. Litterst
PRB 84, 014430 (2011)

Onset temperature Ton for spin freezing, derived from resistivity data, for samples prepared at 285 K.

Super SG behavior in interacting NPs

Superspin glass originating from dipolar interaction with controlled interparticle distance among γ -Fe2O3 nanoparticles with silica shells.
Kosuke Hiroi, Katsuyoshi Komatsu, and Tetsuya Sato
Phys. Rev. B 83, 224424 (2011)

Temperature-dependent magnetization of the samples L12, L14, L18, and L34 under ZFC and FC conditions.
All curves are normalized by the value in Tpeak in the ZFC condition.

See also the article:

Do 8 nm Co Nanocrystals in Long-Range-Ordered Face-Centered Cubic (fcc) Supracrystals Show Superspin Glass Behavior?
Dinah Parker, Isabelle Lisiecki, and M. P. Pileni
J. Phys. Chem. Lett. 1, 1139 (2010)