CERAMICS
INTERNATIONAL
Available online at www.sciencedirect.com
Ceramics International 41 (2015) S185–S190
The effect of Mn doping contents on the structural, dielectric and magnetic
properties of multiferroic Bi
5
Ti
3
FeO
15
Aurivillius ceramics
Kai Tang
a
, Wei Bai
a,
n
, Jia Liu
a
, Jing Yang
a
, Yuanyuan Zhang
a
, Chun-gang Duan
a,b
,
Xiaodong Tang
a,
n
, Junhao Chu
a,b
a
Key Lab of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241, China
b
National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
Received 26 October 2014; accepted 19 March 2015
Available online 2 April 2015
Abstract
Aurivillius Bi
5
Ti
3
FeO
15
(BTFO) multiferroic ceramics with different Mn doping contents were synthesized through the conventional solid state
reaction. The effect of Mn doping on the structural, magnetic and dielectric behaviors of BTFO ceramics is investigated in detail. All these Mn-
doped BTFO ceramics are determined to be layered Aurivillius structure by X-ray diffraction. No microstructure variation of plate-like grains is
obviously confirmed due to Mn doping through field emission scanning electron microscopy. Similar evolution of ε and tan δ with frequency is
found both in BTFO and 10% Mn-doped BTFO ceramics. However, obvious dielectric dispersion phenomena are presented as the Mn-doping
content is beyond 0.1, and this dispersion behavior becomes strong with increasing Mn-doping content, clearly indicated by the appearance of
dielectric loss relaxation peaks. Finally, the same magnetic orders of 10% Mn-doped BTFO ceramics as those of the BTFO one are
unambiguously found while weak ferromagnetism is observed in BTFO ceramics with Mn-doping content beyond 0.2.
& 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Keywords: Aurivillius compound; Mn-doped Bi
5
Ti
3
FeO
15
ceramics; Dielectric and magnetic properties
1. Introduction
Single-phase multiferroic materials with Aurivillius struc-
ture of the general formula Bi
4
Bi
n3
Ti
3
Fe
n3
O
3n þ 3
(nZ 4)
have been widely studied in recent years because of the
coexistence of ferroelectric order and magnetic order [1–8],
and especially the associated electric/magnetic polarization
coupling between the two different orders [9–11]. This could
drive Aurivillius family to be qualified in new application
fields, such as magnetic sensors, multi-state storages and
spintronics and so on, besides ferroelectric random access
memory (FeRAM) and piezoelectric actuators. Four-layer
Bi
5
Ti
3
FeO
15
(BTFO, n= 4) is a typical member of Aurivillius
multiferroic family, composed of a four-layer pseudo perovs-
kite (Bi
3
Ti
3
FeO
13
)
2
sandwiched by two layers of fluorite-like
(Bi
2
O
2
)
2 þ
structure along c axis. Structural, electric, magnetic,
optical, magnetoelectric (ME) properties and elect ronic struc-
ture of BTFO compound with ceramic and film forms have
been widely investigated [1–8]. Ferroelectric Curie tempera-
ture (T
c
) was determined to be about 730 1C along with space
group transition from A2
1
am to I4/mmm [12]. However, with
respect to its magnetic proper ties, superparamagnetic (SPM)
state with local antiferromagnetic (AFM) interaction [4], and
AFM ordering [7] and even weak ferromagnetism in para-
magnetic background [3] have been reported controversially in
BTFO compounds. These results indicate the weak magnetic
nature of BTFO compound. Because of the magnetic nature,
small ME coefficient ( 0.1 mV cm
1
Oe
1
) [7] and weak
magnetocapacitance (MC) effect [8] were recorded in BTFO
samples.
Therefore, researchers have adopted various do ping ele-
ments to enhance the magnetic properties and spin–lattice
coupling. For example, the coexistence of room-temperature
(RT) ferroelectric and ferromagnetic orderings (magnetic Curie
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0272-8842/& 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
n
Corresponding authors.
E-mail addresses: wbai@mail.sitp.ac.cn (W. Bai),
xdtang@sist.ecnu.edu.cn (X. Tang).