Electric‐Field Control of Magnetic Order: From FeRh to Topological Antiferromagnetic Spintronics

Abstract

approach that is capable of suppressing Joule heating is highly desirable from an energy perspective.Under this background, electric-field control of magnetism emerges in the field of multiferroics, which is expected to reduce the energy consumption of information storage by several orders of magnitude, to fJ bit −1 or even aJ bit −1 . [4][5][6][7][8][9][10][11] In single-phase multiferroic materials, which consists of more than one ferroic order, if there is coupling among different ferroic orders, for example, the magnetoelectric coupling between the ferroelectric (FE) and FM orders, the magnetism can be conveniently controlled by electrical switching of the ferroelectricity, such as in YMnO 3 , BiFeO 3 , and TbMnO 3 . However, the magnetic order in these materials is typically antiferromagnetic, which is difficult to detect, and the magnetoelectric coupling is rather weak; [12][13][14] moreover, intrinsic single-phase multiferroic materials are rare because of contradicting symmetry and physical requirements. [15] All these factors prevent single-phase multiferroic materials from practical device applications.Alternatively, the electric-field control of magnetism can be achieved in heterostructures via other means: (1) in FM/FE composite heterostructures, the magnetism of the FM thin films can be modulated by the piezoelectric strain triggered by electric fields applied onto the ferroelectric substrates; [8] (2) in FM/dielectric composite heterostructures with ultrathin FM thin films, the magnetism can be tailored by the electrostatic doping; [8] (3) in FM/multiferroic composite heterostructures, the magnetism of the FM thin film layers can be varied by electric fields through the interfacial magnetic exchange coupling, such as in Co 0.9 Fe 0.1 /BiFeO 3 heterostructures. [16] Typically, the modulation of magnetism by electric fields in multiferroic heterostructures results in variations in the magnetization, coercivity fields, or magnetic anisotropy of the ferromagnetic materials. In addition, the key scientific issue of controlling magnetic properties using an electric field has been carefully elaborated in previous Reviews. [17,18] Among them, the change of magnetization (ΔM) upon external electric fields (ΔE) yields the simplified magnetoelectric coupling coefficient (strictly speaking, the magnetoelectric coupling coefficient should be described as a tensor; please refer to the previous Reviews) [17,18] α = μ 0 ΔM/ΔE, where μ 0 is the permittivity of free space. Compared with single-phase multiferroics, α in multiferroic heterostructures can be significantly greater, for example, it reaches 1.08 × 10 −7 s m −1 Using an electric field instead of an electric current (or a magnetic field) to tailor the electronic properties of magnetic materials is promising for realizing ultralow-energy-consuming memory devices because of the suppression of Joule heating, especially when the devices are scaled down to the nanoscale. Here, recent results on giant magnetization and resistivity modulation in a metamagnetic inte...

Integration of the noncollinear antiferromagnetic metal Mn3Sn onto ferroelectric oxides for electric-field control

“…More importantly, we have further demonstrated a proof-of-concept of an electric-fieldcontrolled topological antiferromagnetic spintronic device [20,23] based on a Mn3Sn thin film that has been highly desired from the perspective of energy consumption.…”

Antiferromagnetic Piezospintronics

“…An important aspect about ferromagnetic/ferroelectric heterostructures for memory applications is the ultralow energy consumption. When one conveniently uses electric field‐generated strain from the ferroelectric material to modify the magnetic and/or electrical properties of the ferromagnetic materials, Joule heating is largely suppressed because of the highly insulating nature of ferroelectric materials, which can potentially lead to extremely small power consumption during information writing, aJ per bit . Thus, piezoelectric strain control provides a superior approach for the contemporary aJ information technique.…”

“…a,b) Schematics of low‐temperature noncollinear and high‐temperature collinear antiferromagnetic phase of Mn 3 Pt, respectively. Reproduced with permission . Copyright 2018, Wiley.…”

Noncollinear spintronics and electric-field control: a review

“…In addition, we would like to briefly comment on the magnetic thin film growth on common ferroelectric single-crystal substrates such as PMN-PT and BaTiO3 and relevant electrical measurements, which may be useful for future studies. Based on our research experience, a too high deposition temperature of antiferromagnetic intermetallic thin films in sputter could always lead to ferromagnetic defects such as in MnPt [54] due to the large surface energy difference between intermetallic materials and oxide substrates at high temperatures and the resulting wetting issue [14,55]. Therefore, for fabricating antiferromagnetic thin films, it is better to perform depositions at relatively low temperature, for example, below 450 ˚C.…”

“…Nowadays, tuning the electron spin by electric field instead of current is a high-efficiency method which could avoid useless energy loss. In our previous work, we have imposed the electric-field manipulation in collinear magnetic materials, thus tailoring the magnetic phase transitions in ferromagnetic FeRh [14] and demonstrating a collinear antiferromagnetic memory device based on MnPt [15]. In this Review, we will first introduce the exotic structure and attractive physical effects in noncollinear spin materials.…”