Reversible Tuning of Magnetization in a Ferromagnetic Ruddlesden–Popper‐Type Manganite by Electrochemical Fluoride‐Ion Intercalation

Abstract

Electrical tuning of materials' magnetic properties is of great technological interest, and in particular reversible on/off switching of ferromagnetism can enable various new applications. Reversible magnetization tuning in the ferromagnetic Ruddlesden–Popper manganite La2−2xSr1+2xMn2O7 by electrochemical fluoride‐ion (de)intercalation in an all‐solid‐state system is demonstrated for the first time. A 67% change in relative magnetization is observed with a low operating potential of <1 V, negligible capacity fading, and high Coulombic efficiency. This system offers a high magnetoelectric voltage coefficient, indicating high energy efficiency. This method can also be extended to tune other materials' properties in various perovskite‐related materials.

Boosting Room‐Temperature Magneto‐Ionics in a Non‐Magnetic Oxide Semiconductor

“…The TiN buffer layer was grown by reactive sputtering using the conditions reported in ref. [37]. TiN was selected because of its conductivity and thermal stability allowing proper growth of the Co 3 O 4 film which was carried out at 200 °C by plasma enhanced atomic layer deposition.…”

“…[22] Recently, via a proton-based approach, excellent endurance and 10 −1 s (10 Hz) room-temperature operation has been shown feasible in spite of certain instability since hydrogen retention is limited. [29] Moreover, voltage-induced changes of magnetization have also been achieved by the insertion/removal of ions other than oxygen, such as Li [35,36] or F. [37] An alternative approach is the use of structural oxygen (selfcontained in the magnetic material of interest), hence avoiding the need of external oxygen sources. [26] This has been shown in electrolyte-gated paramagnetic Co 3 O 4 films, in which roomtemperature voltage-controlled on-off ferromagnetism has been achieved by electric switching of the oxidation state of cobalt (i.e., voltage-driven reduction/oxidation), taking advantage of the defect-assisted voltage-driven migration of structural oxygen.…”

Voltage-driven motion of nitrogen ions: a new paradigm for magneto-ionics

“…agneto-ionics [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] , i.e., the change in the magnetic properties of materials due to electric field-induced ion motion, is acquiring a leading role, among other magnetoelectric mechanisms (intrinsic 18 or extrinsic 19 multiferroicity, electric charge accumulation [20][21][22], to control magnetism with voltage 23,24 . This is triggered by its capability to largely modulate magnetic properties in a permanent and energy-efficient way 2,25 .…”

Voltage-driven motion of nitrogen ions: a new paradigm for magneto-ionics

“…Magneto-ionics [1][2][3][4][5][6][7][8][9][10][11][12][13][14] , i.e., the change in the magnetic properties of materials due to electric-fieldinduced ion motion, is acquiring a leading role, among other magnetoelectric mechanisms (intrinsic 15 or extrinsic 16 multiferroicity, electric charge accumulation [17][18][19] , to control magnetism with voltage 20,21 . This is triggered by its capability to largely modulate magnetic properties in a permanent and energy-efficient way 2,22 .…”

“…Hydrogen is mainly adsorbed rather than absorbed, which imposes stringent limitations on the thickness of the ferromagnet. Other approaches relying on the insertion/removal of ions, such as Li [11][12][13]25 or F 14 , into a ferromagnet are promising in terms of reversibility. However, due to incompatibilities with CMOS architectures, applications in electronics are limited 9 .…”