Effect of aggregates on the magnetization property of ferrofluids: A model of gaslike compression
The effect of field-induced aggregation of particles on the magnetization property of ferrofluids is investigated. From the viewpoint of energy, magnetizability of ferrofluids is more complicated than predicted by Langevin theory because the aggregation, i.e., the transition of ferrofluid microstruc...
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| Format: | Article |
| Language: | English |
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Taylor & Francis Group
2007-01-01
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| Series: | Science and Technology of Advanced Materials |
| Online Access: | http://www.iop.org/EJ/abstract/1468-6996/8/6/A02 |
| _version_ | 1818031886228783104 |
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| author | Jian Li, Yan Huang, Xiaodong Liu, Yueqing Lin, Lang Bai and Qiang Li |
| author_facet | Jian Li, Yan Huang, Xiaodong Liu, Yueqing Lin, Lang Bai and Qiang Li |
| author_sort | Jian Li, Yan Huang, Xiaodong Liu, Yueqing Lin, Lang Bai and Qiang Li |
| collection | DOAJ |
| description | The effect of field-induced aggregation of particles on the magnetization property of ferrofluids is investigated. From the viewpoint of energy, magnetizability of ferrofluids is more complicated than predicted by Langevin theory because the aggregation, i.e., the transition of ferrofluid microstructure, would consume the energy of the applied magnetic field. For calculating the effect of aggregates on the magnetization of ferrofluids, a model of gaslike compression (MGC) is proposed to simulate the evolution of the aggregate structure. In this model, the field-induced colloidal particles aggregating in ferrofluids is equivalent to the "gas of the particles" being compressed by the applied magnetic field. The entropy change of the ferrofluid microstructure is proportional to the particle volume fraction in field-induced aggregates phivH. On the basis of the known behavior of ferrofluid magnetization and the aggregate structure determined from the present experiments, phivH is obtained and found to depend on the aggregating characteristic parameter of ferrofluid particles γ in addition to the particle volume fraction in ferrofluids phiv and the strength of applied magnetic field H. The effect of the nonmagnetic surface layer of ferrofluid particles is also studied. The theory of MGC conforms to our experimental results better than Langevin theory. |
| first_indexed | 2024-12-10T05:58:36Z |
| format | Article |
| id | doaj.art-010e8fee89c0406ea89e27a97eac9467 |
| institution | Directory Open Access Journal |
| issn | 1468-6996 1878-5514 |
| language | English |
| last_indexed | 2024-12-10T05:58:36Z |
| publishDate | 2007-01-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | Science and Technology of Advanced Materials |
| spelling | doaj.art-010e8fee89c0406ea89e27a97eac94672022-12-22T01:59:52ZengTaylor & Francis GroupScience and Technology of Advanced Materials1468-69961878-55142007-01-0186448Effect of aggregates on the magnetization property of ferrofluids: A model of gaslike compressionJian Li, Yan Huang, Xiaodong Liu, Yueqing Lin, Lang Bai and Qiang LiThe effect of field-induced aggregation of particles on the magnetization property of ferrofluids is investigated. From the viewpoint of energy, magnetizability of ferrofluids is more complicated than predicted by Langevin theory because the aggregation, i.e., the transition of ferrofluid microstructure, would consume the energy of the applied magnetic field. For calculating the effect of aggregates on the magnetization of ferrofluids, a model of gaslike compression (MGC) is proposed to simulate the evolution of the aggregate structure. In this model, the field-induced colloidal particles aggregating in ferrofluids is equivalent to the "gas of the particles" being compressed by the applied magnetic field. The entropy change of the ferrofluid microstructure is proportional to the particle volume fraction in field-induced aggregates phivH. On the basis of the known behavior of ferrofluid magnetization and the aggregate structure determined from the present experiments, phivH is obtained and found to depend on the aggregating characteristic parameter of ferrofluid particles γ in addition to the particle volume fraction in ferrofluids phiv and the strength of applied magnetic field H. The effect of the nonmagnetic surface layer of ferrofluid particles is also studied. The theory of MGC conforms to our experimental results better than Langevin theory.http://www.iop.org/EJ/abstract/1468-6996/8/6/A02 |
| spellingShingle | Jian Li, Yan Huang, Xiaodong Liu, Yueqing Lin, Lang Bai and Qiang Li Effect of aggregates on the magnetization property of ferrofluids: A model of gaslike compression Science and Technology of Advanced Materials |
| title | Effect of aggregates on the magnetization property of ferrofluids: A model of gaslike compression |
| title_full | Effect of aggregates on the magnetization property of ferrofluids: A model of gaslike compression |
| title_fullStr | Effect of aggregates on the magnetization property of ferrofluids: A model of gaslike compression |
| title_full_unstemmed | Effect of aggregates on the magnetization property of ferrofluids: A model of gaslike compression |
| title_short | Effect of aggregates on the magnetization property of ferrofluids: A model of gaslike compression |
| title_sort | effect of aggregates on the magnetization property of ferrofluids a model of gaslike compression |
| url | http://www.iop.org/EJ/abstract/1468-6996/8/6/A02 |
| work_keys_str_mv | AT jianliyanhuangxiaodongliuyueqinglinlangbaiandqiangli effectofaggregatesonthemagnetizationpropertyofferrofluidsamodelofgaslikecompression |