Magnetic properties of Mn doped ZnO: the role of synthesis route

Abstract

Structural, morphological, optical, magnetic properties and chemical state of the constituent elements of 2 at% Mn doped ZnO samples synthesized by solid state reaction and sol-gel techniques were analyzed. The role of chemical or valency state in tuning the magnetic properties has been investigated. X-ray diffractometer, scanning electron microscope, UV-visible and X-ray photoelectron spectroscopes and superconducting quantum interference device vibrating sample magnetometer (SQUID VSM) were employed for investigation. Mn incorporation in ZnO lattice has been shown by single phase wurtzite structured samples. The presence of defects particularly zinc vacancy (V Zn ) has been evidenced from band tailing. Solid state reaction technique derived sample exhibit strong intrinsic ferromagnetism but sol-gel sample didn't show strong ferromagnetic (FM) ordering. Antiferromagnetic (AFM) interaction is present in both samples. The chemical state of Mn is ?2 for solid state reaction technique derived sample whereas for sol-gel technique derived sample it is a mixed chemical state (exists in both ?2 and ?3 states). Finally, the peculiar magnetic behavior has been interpreted from the interaction between V Zn and d-electrons of Mn 2? and Mn 3? states.

The Magnetic Properties of Sol-Gel Synthesized TM0.03 Zn0.97 O (TM: Mn, Fe, Co and Ni) Nanoparticles: Role of Different Transition Metals

“…Nanostructured thin films of TM:ZnO synthesized by sol‐gel technique with annealing temperature of 500 °C exhibited strong FM . However, TM:ZnO nanoparticles synthesized by sol‐gel technique and annealed at the same temperature (500 °C) did not show any FM . On the other hand, TM:ZnO nanoparticles synthesized by the solid state reaction method with annealing temperature of 500 °C showed intrinsic FM .…”

Effect of two identical 3d transition-metal atoms M doping (M = V, Cr, Mn, Fe, Co, and Ni) on the structural, electronic, and magnetic properties of ZnO

“…Previous theoretical work has confirmed that the Cr doped ZnO is ferromagnetic (FM) even at room temperature , however a high Cr concentration is required. The Mn‐doped ZnO systems have been studied extensively and observed experimentally to have an FM or antiferromagnetic (AFM) coupling . The ZnO containing Fe impurity has been shown to be AFM and FM .…”

Influence of Ion Beam Irradiation on Optical and Magnetic Properties of Transparent Mn Doped ZnO Thin Films, Suitable for Sensor Applications

“…Further a week FM response has been reported in ZnO nanoparticles and described as d 0 ferromagnetism. 27,28 Conflicting experimental reports further indicates that magnetic ordering inside Zn 1−x Mn x O critically depends on growth methods 8,14,15,19,21 annealing temperature 4,6,10,12 and internal defect structure 4,12,16 as well. Low energy irradiation (400 keV Ar 4+ ion-beam) is helpful for creation of particular type defects in a controlled fashion into the target.…”

“…Transition metal (here Mn) doped ZnO thin films have been extensively studied in the past two decades because of their unique and novel optical [1][2][3][4] and magnetic [5][6][7][8][9][10][11][12] properties. However, doping concentration of transition metal (TM) ions is kept small and they are commonly described as dilute magnetic semiconductors (DMS).…”

“…Low energy irradiation (400 keV Ar 4+ ion-beam) is helpful for creation of particular type defects in a controlled fashion into the target. 8,14 Normally Zn 1−x Mn x O films [10][11][12] or nanoparticles 4,8,9 are enriched with various defects types. The Ar beam has no chemical or magnetic effects into the target however it could only induce heavy damage at the Zn and O site of ZnO 14 and generates defects like zinc and oxygen vacancies [V Zn and V O ] and zinc-interstitial [Zn I ] types into the target.…”