The materials commonly known as spin glasses are an unusual class of magnetic metamaterials whose properties eluded explanation for many years. The development of the theory underpinning the behavior of spin glasses is often held up as a classic example of the importance of pursuing a scientific mystery despite a lack of obvious practical value.1 Spin glass is defined as any material which exhibits a transition in magnetic behavior at a critical temperature Tc, below which the material ceases to conform to Curie-Weiss behavior and instead retains a relatively constant magnetization with changing temperature.2 The name spin glass originates from the fact that these magnetic behavior transitions are analogous to the glass transition of a crystalline solid to an amorphous one, with the magnetization of these materials transitioning from a “crystalline” paramagnetic state to an “amorphous” spin glass state. While some of the physics underlying the development of these states remains elusive, an effort to better understand the chemical properties which lead to this behavior has been undertaken. By growing large single crystals from metal combinations which could lead to spin glass formation, the dependence of the spin glass transition on the crystalline structure of the material can be elucidated.3 In this work, the spin glass system La11Mn13−x−yNixAlySn4−δ (0 ≤ x ≤ 3.6; 2.5 ≤ y ≤ 4.9; 0.6≤ δ ≤ 1.1) is described with varying metal concentrations. Interestingly, as manganese is substituted by other non-magnetic metals (Ni or Al) the material loses the characteristic magnetic properties of the spin glass in favor of paramagnetic behavior, leading to magnetic properties which can be tuned by substituting various metals into the lattice. This material is of particular interest due to the complexity of the crystal system (with four Mn sites and four La sites for substitution) as compared with some of the more extensively studied spin glass materials.4-6
1. P. W. Anderson, Physics Today, 1988, 41, 9-11.
2. P. W. Anderson, Physics Today, 1988, 41, 9.
3. J. V. Zaikina, V. S. Griffin and S. E. Latturner, Inorganic chemistry, 2017, 56, 15194-15202.
4. K. Motoya, Journal of the Physical Society of Japan, 1986, 55, 3733-3736.
5. M. Telling, K. Knight, F. Pratt, A. Church, P. Deen, K. Ellis, I. Watanabe and R. Cywinski, Physical Review B, 2012, 85, 184416.
6. H. Nakamura, K. Yoshimoto, M. Shiga, M. Nishi and K. Kakurai, Journal of Physics: Condensed Matter, 1997, 9, 4701.